Iso/nested control for soft mask processing

ABSTRACT

This method includes a method for etch processing that allows the bias between isolated and nested structures/features to be adjusted, correcting for a process wherein the isolated structures/features need to be smaller than the nested structures/features and wherein the nested structures/features need to be reduced relative to the isolated structures/features, while allowing for the critical control of trimming.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is related to commonly owned co-pending U.S.patent application Ser. No. 10/944,463 filed Sep. 20, 2004, and entitled“Iso/Nested Cascading Trim Control with Model Feedback Updates”, whichis hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The invention relates to semiconductor wafer processing. Moreparticularly, the invention relates to processing a wafer havingisolated and nested structures using a soft mask.

BACKGROUND OF THE INVENTION

The use of feed forward controllers in semiconductor processing has longbeen established in the fabrication of semiconductor integrated circuitsby semiconductor manufacturing facilities (fabs). Until recently, waferswere treated as a batch or a lot and the same processing performed oneach of the wafers in the lot. The size of the lot varies depending onthe manufacturing practices of the fab but is typically limited to amaximum of 25 wafers. Measurements were routinely made on a few wafersin the lot and adjustments made to the processing based on these samplemeasurements. This method of control based on sample measurements on thelot and process recipe adjustments for the following lots is calledlot-to-lot control (L2L). The process models and information necessaryto modify the process recipes for L2L control were kept and thecomputations were performed at the fab level. Recently, manufacturers ofsemiconductor processing equipment (SPE) have included the ability tomeasure each wafer immediately before and after the processing isperformed. The capability to measure each wafer on the processing toolis called integrated metrology (IM). IM enabled the ability to measureand adjust the process recipe at the wafer-to-wafer (W2W) level.

The structures on the semiconductor wafers have not only decreased insize but also have increased in density causing additional processingcontrol problems. Areas on semiconductor wafers have been identified asbeing isolated areas or nested areas based on the density of structureswithin the particular area and problems have developed in thesemiconductor processing due to these different densities.

The need for trim etch has become common, with many methods for trimmingthe Critical Dimension (CD) for gate length control. Iso/nested controlhas become part of the mask design process, including the modeling ofthe process through the etcher. The iso/nested model designed into themask making process however is optimized for a single CD target relatedto an isolated or nested structure. As the need to shrink the gate bytrimming and the need to change gate targets change over time, it isexpensive to create new masks and re-optimize the iso/nested bias. Themask bias control is by use of the optical and process correction (OPC),sometimes called optical proximity correction, in which the apertures ofthe reticule are adjusted to add or subtract the necessary light toincrease pattern fidelity. Another approach is phase-shift masks (PSM),in which topographic structures are created on the reticule to introducecontrast-enhancing interference fringes in the image. Another problemcan occur when designers learn after the mask is made that theiso/nested bias requires adjusting to optimize performance after themask is generated and the first setup sample parts are created.

What has not been addressed is a method to adjust the wafer CD biasbetween isolated and nested lines after pattering as part of the etchprocess when a soft mask is used.

SUMMARY OF THE INVENTION

The invention provides a method of operating a semiconductor processingsystem that includes: receiving a wafer that comprises a soft mask layerand a bottom anti-reflective coating (BARC) layer; receiving input datacomprising reference metrology data for the wafer including referencemetrology data for at least one isolated structure on the wafer,reference metrology data for at least one nested structure on the wafer,soft mask data, and BARC data; determining a first value using a featuresize for the at least one isolated structure on the wafer; determining asecond value using a feature size for the at least one nested structureon the wafer; executing an Iso-Greater control strategy when the firstvalue is greater than or equal to the second value, wherein theIso-Greater control strategy comprises an Iso/Nested control plan forcontrolling an iso/nested etching process, a Trim Control plan forcontrolling a trimming process, or a BARC open control plan forcontrolling a BARC etching process, or a combination of two or morethereof; and executing a Nes-Greater control strategy when the firstvalue is less than the second value, wherein the Nes-Greater controlstrategy comprises an Iso/Nested control plan for controlling aniso/nested deposition process, a Trim Control plan for controlling atrimming process, or a BARC open control plan for controlling a BARCetching process, or a combination of two or more thereof.

In one aspect of the invention the procedure for executing anIso-Greater control strategy includes: determining a desired targetvalue for an iso/nested etching process, the target value comprising adesired feature size after performing the iso/nested etching process;calculating an iso-trim value using the difference between the firstvalue and the target value, wherein the first value comprises measureddata for an isolated structure; calculating a dense-trim value using thedifference between the second value and the target value, wherein thesecond value comprises measured data for a nested structure; calculatinga ratio using the iso-trim value and the dense-trim value; executing theiso/nested etching process, wherein recipe settings for achieving thedesired target value have been determined using the calculated ratio;determining a final CD target; calculating a trim value using adifference between the final CD target and the desired target value; andexecuting a trim process, wherein recipe settings for achieving thefinal CD target have been determined using the trim value. In addition,a BARC open process can be executed.

In another aspect of the invention the procedure for executing anotherIso-Greater control strategy includes: determining a desired trim valuefor a trim process, the desired trim value comprising a trim amount tobe removed from the first value and the second value after performingthe trim process, wherein the first value comprises measured data for anisolated structure and the second value comprises measured data for anested structure; executing the trim process, wherein recipe settingsfor achieving the desired trim value have been determined to achieve afirst trimmed value and a second trimmed value; determining a final CDvalue; calculating an iso-trim value using the difference between thefirst trimmed value and the final CD value, wherein the first trimmedvalue comprises the measured data for an isolated structure less thetrim amount; calculating a dense-trim value using the difference betweenthe second trimmed value and the final CD value, wherein the secondtrimmed value comprises measured data for a nested structure less thetrim amount; calculating a ratio using the iso-trim value and thedense-trim value; and executing the iso/nested etching process, whereinrecipe settings for achieving the final CD value have been determinedusing the calculated ratio. In addition, a BARC open process can beexecuted.

In another aspect of the invention the procedure for executing anotherIso-Greater control strategy includes: determining a desired targetvalue for an iso/nested etching process, the target value comprising adesired feature size after performing the iso/nested etching process;calculating an iso-trim value using the difference between the firstvalue and the target value, wherein the first value comprises measureddata for an isolated structure; calculating a dense-trim value using thedifference between the second value and the target value, wherein thesecond value comprises measured data for a nested structure; calculatinga ratio using the iso-trim value and the dense-trim value; executing theiso/nested etching process, wherein recipe settings for achieving thedesired target value have been determined using the calculated ratio;executing a BARC open process; determining a final CD target;calculating a trim value using a difference between the final CD targetand the desired target value; and executing a trim process, whereinrecipe settings for achieving the final CD target have been determinedusing the trim value.

In another aspect of the invention the procedure for executing anotherIso-Greater control strategy includes: determining a desired trim valuefor a trim process, the desired trim value comprising a trim amount tobe removed from the first value and the second value after performingthe trim process, wherein the first value comprises measured data for anisolated structure and the second value comprises measured data for anested structure; executing the trim process, wherein recipe settingsfor achieving the desired trim value have been determined to achieve afirst trimmed value and a second trimmed value; executing a BARC openprocess; determining a final CD value; calculating an iso-trim valueusing the difference between the first trimmed value and the final CDvalue, wherein the first trimmed value comprises the measured data foran isolated structure less the trim amount; calculating a dense-trimvalue using the difference between the second trimmed value and thefinal CD value, wherein the second trimmed value comprises measured datafor a nested structure less the trim amount; calculating a ratio usingthe iso-trim value and the dense-trim value; and executing theiso/nested etching process, wherein recipe settings for achieving thefinal CD value have been determined using the calculated ratio.

In another aspect of the invention the procedure for executing aNes-Greater control strategy includes: determining a desired targetvalue for an iso/nested deposition process, the target value comprisinga desired feature size after performing the iso/nested depositionprocess; calculating an iso-trim value using the difference between thefirst value and the target value, wherein the first value comprisesmeasured data for an isolated structure; calculating a dense-trim valueusing the difference between the second value and the target value,wherein the second value comprises measured data for a nested structure;calculating a ratio using the iso-trim value and the dense-trim value;executing the iso/nested deposition process, wherein recipe settings forachieving the desired target value have been determined using thecalculated ratio; determining a final CD target; calculating a trimvalue using a difference between the final CD target and the desiredtarget value; and executing a trim process, wherein recipe settings forachieving the final CD target have been determined using the trim value.In addition, a BARC open process can be executed.

In another aspect of the invention, the procedure for executing anotherNes-Greater control strategy includes: determining a desired trim valuefor a trim process, the desired trim value comprising a trim amount tobe removed from the first value and the second value after performingthe trim process, wherein the first value comprises measured data for anisolated structure and the second value comprises measured data for anested structure; executing the trim process, wherein recipe settingsfor achieving the desired trim value have been determined to achieve afirst trimmed value and a second trimmed value; determining a final CDvalue; calculating an iso-trim value using the difference between thefirst trimmed value and the final CD value, wherein the first trimmedvalue comprises the measured data for an isolated structure less thetrim amount; calculating a dense-trim value using the difference betweenthe second trimmed value and the final CD value, wherein the secondtrimmed value comprises measured data for a nested structure less thetrim amount; calculating a ratio using the iso-trim value and thedense-trim value; and executing the iso/nested deposition process,wherein recipe settings for achieving the final CD value have beendetermined using the calculated ratio. In addition, a BARC open processcan be executed.

In another aspect of the invention the procedure for executing anotherNes-Greater control strategy includes: determining a desired targetvalue for an iso/nested deposition process, the target value comprisinga desired feature size after performing the iso/nested depositionprocess; calculating an iso-trim value using the difference between thefirst value and the target value, wherein the first value comprisesmeasured data for an isolated structure; calculating a dense-trim valueusing the difference between the second value and the target value,wherein the second value comprises measured data for a nested structure;calculating a ratio using the iso-trim value and the dense-trim value;executing the iso/nested deposition process, wherein recipe settings forachieving the desired target value have been determined using thecalculated ratio; executing a BARC open process; determining a final CDtarget; calculating a trim value using a difference between the final CDtarget and the desired target value; and executing a trim process,wherein recipe settings for achieving the final CD target have beendetermined using the trim value.

In another aspect of the invention the procedure for executing anotherNes-Greater control strategy includes: determining a desired trim valuefor a trim process, the desired trim value comprising a trim amount tobe removed from the first value and the second value after performingthe trim process, wherein the first value comprises measured data for anisolated structure and the second value comprises measured data for anested structure; executing the trim process, wherein recipe settingsfor achieving the desired trim value have been determined to achieve afirst trimmed value and a second trimmed value; executing a BARC openprocess; determining a final CD value; calculating an iso-trim valueusing the difference between the first trimmed value and the final CDvalue, wherein the first trimmed value comprises the measured data foran isolated structure less the trim amount; calculating a dense-trimvalue using the difference between the second trimmed value and thefinal CD value, wherein the second trimmed value comprises measured datafor a nested structure less the trim amount; calculating a ratio usingthe iso-trim value and the dense-trim value; and executing theiso/nested deposition process, wherein recipe settings for achieving thefinal CD value have been determined using the calculated ratio.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of various embodiments of the invention andmany of the attendant advantages thereof will become readily apparentwith reference to the following detailed description, particularly whenconsidered in conjunction with the accompanying drawings, in which:

FIG. 1 shows an exemplary block diagram of a processing system inaccordance with an embodiment of the present invention;

FIG. 2 shows a simplified block diagram of an integrated processingsystem in accordance with an embodiment of the invention;

FIG. 3 shows a simplified block diagram of a processing system inaccordance with an embodiment of the invention;

FIG. 4 shows a simplified block diagram of a control process inaccordance with an embodiment of the invention;

FIG. 5A shows a simplified block diagram of a processing system inaccordance with an embodiment of the invention;

FIG. 5B shows a simplified diagram of a processing system in accordancewith an embodiment of the invention;

FIG. 5C shows a simplified diagram of another processing system inaccordance with an embodiment of the invention;

FIG. 5D shows a simplified diagram of yet another processing system inaccordance with an embodiment of the invention;

FIG. 6A shows a simplified diagram of a further processing system inaccordance with an embodiment of the invention;

FIG. 6B shows a simplified diagram of one additional processing systemin accordance with an embodiment of the invention;

FIG. 6C shows a simplified diagram of another processing system inaccordance with an embodiment of the invention;

FIG. 6D shows a simplified diagram of one further processing system inaccordance with an embodiment of the invention;

FIG. 7 provides an exemplary recipe table, listing various processingparameters in accordance with the invention;

FIG. 8 shows a graph of exemplary trim equations in accordance with anembodiment of the invention;

FIG. 9 shows a simplified block diagram of a cascaded control system inaccordance with an embodiment of the invention;

FIG. 10 shows a simplified sequence diagram for a method of operating aprocessing system in accordance with an embodiment of the invention;

FIG. 11 shows a simplified sequence diagram for method of operating aprocessing system in accordance with another embodiment of theinvention;

FIG. 12 shows a simplified sequence diagram for method of operating aprocessing system in accordance with another embodiment of theinvention;

FIG. 13 shows exemplary results in accordance with an embodiment of theinvention;

FIG. 14 shows additional exemplary results in accordance with anembodiment of the invention;

FIG. 15 shows a simplified flow diagram of another procedure inaccordance with another embodiment of the invention;

FIG. 16 illustrates an exemplary view of an Iso/Nested Control StrategyScreen in accordance with an embodiment of the invention;

FIG. 17 illustrates an exemplary view of a Nested Control Plan EditorScreen in accordance with an embodiment of the invention;

FIG. 18 illustrates an exemplary view of a Isolated Control Plan EditorScreen in accordance with an embodiment of the invention; and

FIG. 19 illustrates an exemplary view of a Formula Model Editor Screenin accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF SEVERAL EMBODIMENTS

Various embodiments of the present invention are discussed below. Whereappropriate, like reference numerals are used to refer to like features.The embodiments presented herein are intended to be merely exemplary ofthe wide variety of embodiments contemplated within the scope of thepresent invention, as would be appreciated by those skilled in the art.Accordingly, the invention is not limited solely to the embodimentspresented but also encompasses any and all variations and equivalentsthat would be appreciated by those skilled in the art.

In semiconductor processing, the etch results tend to differ based onthe geometry of the features. For example, features can include narrowfeatures and spaces, wide features and spaces, isolated features andspaces, and nested features and spaces. Some of these features can havedifferent etch rates, and the different etch rates can create problemduring the manufacturing process. The present invention provides amethod and apparatus for processing features having differentcharacteristics to improve performance of the semiconductor devicesproduced thereby.

FIG. 1 shows an exemplary block diagram of a processing system inaccordance with an embodiment of the present invention. In theillustrated embodiment, processing system 100 comprises a processingtool 110, a controller 120 coupled to the processing tool 110, and amanufacturing equipment system (MES) 130 coupled to the controller 120.In addition, at least one of the processing tool 110, the controller120, and the MES 130 can comprise a GUI component and/or a databasecomponent (not shown). In alternate embodiments, the GUI componentand/or the database component are not required.

The system components 110, 120, and 130 can include memory (not shown)for storing information and instructions to be executed by the system100. In addition, the memory may be used for storing temporary variablesor other intermediate information during the execution of instructionsby the various processors in the system 100. One or more of the systemcomponents 110, 120, and 130 can comprise the means for reading dataand/or instructions from a computer readable medium. In addition, one ormore of the system components 110, 120, and 130 can comprise the meansfor writing data and/or instructions to a computer readable medium.

The semiconductor processing system 100 performs a portion of or all ofthe processing steps of the invention in response to the controller 120executing one or more sequences of one or more instructions contained ina memory. Such instructions may be received by the controller 120 fromanother computer, a computer readable medium, or a network connection.

Stored on any one or on a combination of computer readable media, thepresent invention includes software for controlling the semiconductorprocessing system 100, for driving a device or devices for implementingthe invention, and for enabling the semiconductor processing system 100to interact with a human user. Such software may include, but is notlimited to, device drivers, operating systems, development tools, andapplications software. Such computer readable media further includes thecomputer program product of the present invention for performing all ora portion (if processing is distributed) of the processing performed inimplementing the invention.

The term “computer readable medium” as used herein refers to any mediumthat participates in providing instructions to the processor forexecution. A computer readable medium may take many forms, including butnot limited to, non-volatile media, volatile media, and transmissionmedia. Non-volatile media include, for example, optical, magnetic disks,and magneto-optical disks. Volatile media include, but are not limitedto, a dynamic memory, and transmission media include, among otherexamples, coaxial cables, copper wire and fiber optics. Transmissionmedia also may take the form of acoustic or light waves, such as thosegenerated during radio wave and infrared data communications (e.g.,wireless transmission media).

Links 122 and 124 can provide hardwired two-way data communicationpaths. Alternately, wireless links may also be implemented. The links122 and 124 may provide a connection to another computer through a localnetwork. The links 122 and 124 can be used to transmit and/or receivedata. In addition, the links 122 and 124 may provide a connection to amobile device such as a personal digital assistant (PDA) laptopcomputer, or cellular telephone, to name but a few examples.

Some setup and/or configuration information can be obtained by theprocessing tool 110 and/or the controller 120 from the factory system130. Factory level business rules can be used to establish a controlhierarchy. For example, the processing tool 110 and/or the controller120 can operate independently, or can be controlled to some degree bythe factory system 130. In addition, factory level business rules can beused to determine when a process is paused and/or stopped, and what isdone when a process is paused and/or stopped. In addition, factory levelbusiness rules can be used to determine when to change a process and howto change the process.

Business rules can be used to specify the action taken for normalprocessing and the actions taken on exceptional conditions. The actionscan include, for example: initial model loading, pre-etch metrology datafiltering, controller recipe selection, post-etch metrology datafiltering, feedback calculation, and a model update.

Business rules can be defined at a control strategy level, a controlplan level or a control model level. Business rules can be assigned toexecute whenever a particular context is encountered. When a matchingcontext is encountered at a higher level as well as a lower level, thebusiness rules associated with the higher level can be executed. GUIscreens can be used for defining and maintaining the business rules.Business rule definition and assignment can be allowed for users withgreater than normal security level. The business rules can be maintainedin the database. Documentation and help screens can be provided on howto define, assign, and maintain the business rules.

The MES 130 can monitor some system processes using data reported fromthe databases associated with the processing tool 110 and/or thecontroller 120. Factory level business rules can be used to determinewhich processes are monitored and which data is used. For example, theprocessing tool 110 and/or the controller 120 can independently collectdata, or the data collection process can be controlled to some degree bythe factory system 130. In addition, factory level business rules can beused to determine how to manage the data when a process is changed,paused, and/or stopped.

In addition, the MES 130 can provide run-time configuration informationto the processing tool 110 and/or the controller 120. For example,automated process control (APC) settings, targets, limits, rules, andalgorithms can be downloaded from the factory to the processing tool 110and/or the controller 120 as an “APC recipe”, an “APC system rule”, and“APC recipe parameters” at run-time.

Some setup and/or configuration information can be determined by theprocessing tool 110 and/or the controller 120 when they are initiallyconfigured by the system 100. System level business rules (system rules)can be used to establish a control hierarchy. For example, theprocessing tool 110 and/or the controller 120 can operate independently,or the processing tool 110 can be controlled to some degree by thecontroller 120. In addition, system rules can be used to determine whena process is paused and/or stopped, and what is done when a process ispaused and/or stopped. In addition, system rules can be used todetermine when to change a process and how to change the process.Furthermore, the controller 120 can use tool level rules to control sometool level operations.

In general, rules allow system and/or tool operation changes based onthe dynamic state of the system 100.

In FIG. 1, one processing tool 110, and one controller 120 are shown,but this is not required for the invention. The semiconductor processingsystem 100 can comprise any number of processing tools having any numberof controllers associated with them in addition to independent processtools and modules.

The processing tool 110 and/or the controller 120 can be used toconfigure any number of processing tools having any number of processingtools associated with them in addition to any number of independentprocess tools and modules. The processing tool 110 and/or the controller120 can collect, provide, process, store, and display data fromprocesses involving processing tools, processing subsystems, processmodules, and sensors.

The processing tool 110 and/or the controller 120 can comprise a numberof applications including at least one tool-related application, atleast one module-related application, at least one sensor-relatedapplication, at least one interface-related application, at least onedatabase-related application, at least one GUI-related application, andat least one configuration application.

For example, the system 100 can comprise an APC system from TokyoElectron Limited that can include a Unity Tool™, Telius Tool™, and/or aTrias Tool™ and their associated processing subsystems and processmodules. In addition, the system can comprise a run-to-run (R2R)controller, such as the Ingenio TL ES (Tool Level Etch System) serverfrom Tokyo Electron Limited, and an integrated metrology module (IMM)from Tokyo Electron Limited. Alternately, the controller 120 can supportother process tools and other process modules.

A GUI component (not shown) can provide easy to use interfaces thatenable users to: view tool status and process module status; create andedit x-y charts of summary and raw (trace) parametric data for selectedwafers; view tool alarm logs; configure data collection plans thatspecify conditions for writing data to the database or to output files;input files to statistical process control (SPC) charting, modeling andspreadsheet programs; examine wafer processing information for specificwafers, and review data that is currently being saved to the database;create and edit SPC charts of process parameters, and set SPC alarmswhich generate e-mail warnings; run multivariate PCA (PrincipalComponent Analysis) and/or PLS (Partial Least Squares) models; and viewdiagnostics screens in order to troubleshoot and report problems withthe TL (Tool Level) controller 120.

Raw data and trace data from the tool can be stored as files in adatabase. In addition, IM (Integrated Metrology) data and host metrologydata can be stored in the database. The amount of data depends on thedata collection plans that are configured, as well as the frequency withwhich processes are performed and processing tools are run. The dataobtained from the processing tools, the processing chambers, thesensors, and the operating system can be stored in the database.

In an alternate embodiment, the system 100 can comprise a clientworkstation (not shown). The system 100 can support a plurality ofclient workstations. A client workstation can allow a user to performconfiguration procedures; to view status including tool, controller,process, and factory status; to view current and historical data; toperform modeling and charting functions; and to input data to thecontroller. For example, a user may be provided with administrativerights that allow him to control one or more processes performed by acontroller.

The processing tool 110 and the controller 120 can be coupled to the MES130 and can be part of an E-Diagnostic System. The processing tool 110and/or the controller 120 can exchange information with a factorysystem. In addition, the MES 130 can send command and/or overrideinformation to the processing tool 110 and/or the controller 120. Forexample, the MES 130 can feed-forward to the processing tool 110 and/orthe controller 120 downloadable recipes for any number of processmodules, tools, and measuring devices, with variable parameters for eachrecipe. Variable parameters can include final CD targets, limits,offsets, and variables in the tool level system that needs to beadjustable by lot. In addition, factory litho CD metrology data can befeed-forwarded to controller 120.

Furthermore, the MES 130 can be used to provide measurement data, suchas CD SEM (Critical Dimension-Scanning Electron Microscope) information,to the controller 120. Alternately, the CD SEM information can beprovided manually. Adjustment factors are used to adjust for any offsetbetween the IM and CD SEM measurements. Manual and automated input of CDSEM data includes a timestamp, such as a date, for proper insertion into the history of the FB (Feed Back) control loop in the R2R controller.

Configurable items can be configured as a set of variable parameterssent from the factory system using GEM SECS (Generic EquipmentModel/SEMI Equipment Communication Standard) communications protocol.For example, variable parameters can be passed as part of an “APCRecipe”. An APC recipe may contain more than one sub recipes and eachsub recipe can contain variable parameters.

A single processing tool 110 is shown in FIG. 1, but this is notrequired for the invention. Alternately, additional processing tools canbe used. In one embodiment, a processing tool 110 can comprise one ormore processing modules. The processing tool 110 can comprise at leastone of an etch module, a deposition module, a polishing module, acoating module, a developing module, and a thermal treatment module,among others.

The processing tool 110 can comprise links 112 and 114 for coupling toat least one other processing tool and/or at least one other controller.For example, other processing tools and/or controllers can be associatedwith a process that has been performed before this process, and/or othercontrollers can be associated with a process that is performed afterthis process. The link 112 and the link 114 can be used to feed forwardand/or feed back information. For example, feed forward information cancomprise data associated with an incoming wafer. This data can includelot data, batch data, run data, composition data, and wafer historydata. The data can comprise pre-process data that can be used toestablish an input state for a wafer. A first part of the pre-processdata can be provided to the controller 120, and a second part of thepre-process data can be provides to the processing tool 110.Alternately, the two parts can comprise the same data.

The processing tool 110 can comprise a single integrated metrologymodule (IMM) device (not shown) or multiple measurement devices. Thesystem 100 can include module related measurement devices, tool-relatedmeasurement devices, and external measurement devices. For example, datacan be obtained from sensors coupled to one or more process modules andsensors coupled to the processing tool. In addition, data can beobtained from an external device such as a SEM (Scanning ElectronMicroscope) tool and an Optical Digital Profiling (ODP) tool. An ODPtool is available for Timbre Technologies Inc. (a TEL (Tokyo ElectronLimited) company) that provides a patented technique for measuring theprofile of a structure in a semiconductor device. For example, ODPtechniques can be used to obtain CD information, structure profileinformation, or via profile information.

ODP techniques for creating a metrology model are taught in co-pendingU.S. patent application Ser. No. 10/206,491, entitled “Model andParameter Selection in Optical Metrology” by Voung, et al., filed onJul. 25, 2002 and ODP techniques covering integrated metrologyapplications are taught in U.S. Pat. No. 6,785,638, entitled METHOD ANDSYSTEM OF DYNAMIC LEARNING THROUGH A REGRESSION-BASED LIBRARY GENERATIONPROCESS, filed on Aug. 6, 2001, and both of which are incorporated byreference herein.

The controller 120 is coupled to the processing tool 110 and the MES130, and information such as pre-processing data and post-processingdata can be exchanged between them. For example, when an internal resetevent is being generated from the tool 110, the controller 120 can senda message, such as an alarm, to the MES 130. This can allow the factorysystem and/or factory personnel to make the necessary changes tominimize the number of wafers at risk after a major change occurs suchas those that occur during corrective or preventative maintenance.

A single controller 120 is also shown in FIG. 1, but this is notrequired for the invention. Alternately, additional controllers can beused. For example, the controller 120 can comprise a run-to-run (R2R)controller, a feed-forward (FF) controller, process model controller,feedback (FB) controller, or a process controller, or a combination oftwo or more thereof (all not shown in FIG. 1).

The controller 120 can comprise links 122 and 124 for coupling to atleast one other controller. For example, other controllers can beassociated with a process that has been performed before this process,and/or other controllers can be associated with a process that isperformed after this process. The link 122 and the link 124 can be usedto feed forward and/or feed back information.

The controller 120 can use the difference between a measured criticaldimension of the incoming material (input state) and a target criticaldimension (desired state) to predict, select, or calculate a set ofprocess parameters to achieve a desired process result that is changingthe state of the wafer from the input state to the desired state. Forexample, this predicted set of process parameters can be a firstestimate of a recipe to use based on an input state and a desired state.In one embodiment, data such the input state and/or the desired statedata can be obtained from a host.

In one case, the controller 120 knows the input state and a modelequation for the desired state for the wafer, and the controllerdetermines a set of recipes that can be performed on the wafer to changethe wafer from the input state to a processed state. For example, theset of recipes can describe a multi-step process involving a set ofprocess modules.

The time constant for the controller 120 can be based on the timebetween measurements. When measured data is available after a lot iscompleted, the controller's time constant can be based on the timebetween lots. When measured data is available after a wafer iscompleted, the controller's time constant can be based on the timebetween wafers. When measurement data is provided real-time duringprocessing, the controller's time constant can be based on processingsteps, within a wafer. When measured data is available while a wafer isbeing processed or after a wafer is completed or after the lot iscompleted, the controller 120 can have multiple time constants that canbe based on the time between process steps, between wafers, and/orbetween lots.

One or more controllers can be operating at any point in time. Forexample, one controller can be in an operating mode while a secondcontroller can be in a monitoring mode. In addition, another controllercan be operating in a simulation mode. A controller can comprise asingle loop or multiple loops, and the loops can have different timeconstants. For example, loops can be dependent on wafer timing, lottiming, batch timing, chamber timing, tool timing, and/or factorytiming, among other parameters.

The controller 120 can compute a predicted state for the wafer based onthe input state, the process characteristics, and a process model. Forexample, a trim rate model can be used along with a processing time tocompute a predicted trim amount. Alternately, an etch rate model can beused along with a processing time to compute an etch depth, and adeposition rate model can be used along with a processing time tocompute a deposition thickness. In addition, models can include SPC(Statistical Process Control) charts, PLS (Partial Least Squares)models, PCA (Principle Component Analysis) models, Fitness DistanceCorrelation (FDC) models, and Multivariate Analysis (MVA) models.

The controller 120 can receive and utilize externally provided data forprocess parameter limits in a process module. For example, thecontroller GUI component provides a means for the manual input of theprocess parameter limits. In addition, a factory level controller canprovide limits for process parameters for each process module.

The controller 120 can receive and execute models created bycommercially available modeling software. For example, the controllercan receive and execute models (PLS, PCA, etc.) that were created byexternal applications and sent to the controller 120.

The controller 120 can comprise one or more filters (not shown) tofilter the metrology data in order to remove any random noise. Anoutlier filter can be used to remove outliers that are statically notvalid and should not be considered in the calculation of the mean of awafer measurement. A noise filter can be used to remove random noise andstabilize the control loop, an Exponentially Weighed Moving Average(EWMA) or Kalman filter can be applied.

The controller 120 can send and receive notification of an exceptioncondition. For example, the controller 120 can send and receivenotifications to and from a factory level controller or a tool levelcontroller. In addition, a notification can be sent via thee-Diagnostics network, e-mail, or pager after the identification of anexception condition.

The controller 120 can comprise a database component for archiving inputand output data. For example, the controller 120 can archive receivedinputs, sent outputs, and actions taken by the controller 120 in asearchable database. In addition, the controller 120 can comprise meansfor data backup and restoration. In addition, the searchable databasecan include model information, configuration information, and historicalinformation and the controller 120 can use the database component tobackup and restore model information and model configuration informationboth historical and current.

The controller 120 can comprise a web based user interface. For example,the controller 120 can comprise a web enabled GUI component for viewingthe data in the database. The controller 120 can comprise a securitycomponent that can provide for multiple levels of access depending onthe permissions granted by a security administrator. The controller 120can comprise a set of default models that are provided at installationtime, so that the controller 120 can reset to default conditions.

The controller 120 can take various actions in response to an exception,depending on the nature of the exception. The actions taken on exceptioncan be based on the business rules established for the context specifiedby the system recipe, process recipe, module type, module identificationnumber, load port number, cassette number, lot number, control job ID,process job ID and/or slot number.

The controller 120 has the capability of managing multiple processmodels that are executed at the same time and are subject to differentsets of process-recipe constraints. The controller 120 can run in threedifferent modes: simulation mode, test mode, and standard mode. Thecontroller 120 can operate in simulation mode in parallel with theactual process mode.

When the semiconductor processing system 100 includes a host system andone or more processing systems, the host system can operate as themaster system and can control and/or monitor a major portion of theprocessing operations. The host system can create a process sequence,and can send the process sequence to the processing system 100. In oneembodiment, the process sequence can comprise a sequence of measurementmodule visits and processing module visits. A process job (PJ) can becreated for each measurement module visit and each processing modulevisit.

In addition, virtual measurements can be made when a processing systemcontroller executes a simulation model. The results from simulationmodel executions can be stored and tracked as virtual measurements.

FIG. 2 shows a simplified block diagram of an integrated processingsystem in accordance with an embodiment of the invention. In theillustrated embodiment, a processing system (TELIUS™) is shown thatcomprises a processing tool, an integrated metrology module (IMM), and atool level Advanced Process Control (APC) controller.

A system such as shown in FIG. 2 can provide IMM wafer sampling and thewafer slot selection can be determined using a function such as a PJCreate function. The R2R control configuration can include feed forwardcontrol plan variables, feedback control plan variables, metrologycalibration parameters, control limits, and SEMI (SemiconductorEquipment and Materials International) Standard variable parameters.Metrology data reports can include wafer, site, structure, andcomposition data, and the tool can report actual settings for the wafer.

The IMM system can include an optical measuring system such as a TimbreTechnologies' Optical Digital Profilometry (ODP™) system that usesspectroscopic ellipsometry, reflectometry, or other optical instrumentsto measure true device profiles, accurate critical dimensions (CD), andmultiple layer film thickness of a wafer. The process is executedin-line, which eliminates the need to break the wafer for performing theanalyses. ODP™ can be used with the existing thin film metrology toolsfor inline profile and CD measurement, and can also be integrated withTEL (Tokyo Electron Limited) processing tools to provide real-timeprocess monitoring and control. ODP™ Profiler™ can be used both as ahigh precision metrology tool to provide actual profile, CD, and filmthickness results, and a yield enhancement tool to detect in-lineprocess excursion or process faults.

ODP™ solution has three key components: ODP™ Profiler™ Library comprisesan application specific database of optical spectra and itscorresponding semiconductor profiles, CDs, and film thicknesses.Profiler™ Application Server (PAS) comprises a computer server thatconnects with optical hardware and computer network. It handles the datacommunication, ODP library operation, measurement process, resultsgeneration, results analysis, and results output. The ODP™ Profiler™Software includes the software installed on PAS to manage measurementrecipe, ODP™ Profiler™ library, ODP™ Profiler™ data, ODP™ Profiler™results search/match, ODP™ Profiler™ results calculation/analysis, datacommunication, and PAS interface to various metrology tools and computernetwork.

A control system, such as Ingenio ES system (Ingenio is a trademark ofTokyo Electron Limited and ES is an abbreviation for “Etch System”) fromTokyo Electron Limited, can comprise management applications, such asthe Ingenio Recipe Management application. For example, the IngenioRecipe Management can be used to view and/or control a recipe stored inthe Ingenio ES Management Sever recipe database that is synchronizedwith equipment via a network environment from the Ingenio ES Client. AnIngenio ES Client, which can be placed separately at a distance from thefactory, provides comprehensive management functions to multipleequipment units. Ingenio Recipe Management, as an Ingenio ES Clientutility, can comprise a management application to view and control arecipe stored in the Ingenio ES, and an application to edit recipe datastored in the Ingenio ES Management Sever.

Recipes can be organized in a tree structure that can comprise recipesets, classes, and recipes that can be displayed as objects. Recipes caninclude process recipe data, system recipe data, and IMM recipe data.Data can be stored and organized using recipe set. For example, therecipes sets can include an equipment recipe set, a backup recipe set,and a user recipe set. In addition, the data can be organized by class,and classes can include SYSTEM, PM, LLM, and IMM classes. Fordefinitional purposes, SYSTEM refers to system level objects, PM refersto process module objects, LLM refers to load lock module objects, andIMM refers to integrated metrology module objects.

The IMM recipes that are on the processing tool can be used to determinewafer sampling and relationship between slots and IM recipes. IM recipescan exist on IM measurement hardware, can be selected in Telius IMMrecipes, can contain pattern recognition information, can be used toidentify the chips to sample on each wafer, and can be used to determinewhich PAS recipe to use. PAS recipes can be used to determine which ODPlibrary to use, and to define the measurement metrics to report, such asCD, SWA, thickness, trench width, and GOF. For definitional purposes,SWA refers to side wall angle and GOF refers to goodness of fit.

Ingenio APC recipes operate as control strategies, and a controlstrategy can be associated with a processing tool recipe, such as aTelius System Recipe. Wafer level context matching at runtime allows forcustom configuration by wafer (slot, waferID, lotID, etc.). A controlstrategy can include one or more control plans, and a process moduleand/or measurement module that is being controlled has at least onecontrol plan defined for a visit to the process module and/ormeasurement module. Control plans can contain models, control limits,targets, and can include static recipes, formula models, and feedbackplans.

Control plans can cover multiple process steps within a module, and canbe controlled by the factory. Parameter ranges can be defined for eachprocess and/or measurement module, and variable parameter “Limit Ranges”are provided for each control parameter.

FIG. 3 shows a simplified block diagram of a processing system inaccordance with an embodiment of the invention. In the illustratedembodiment, a (TELIUS™) processing tool is shown and an integratedmetrology (IM) tool is shown.

Spectral data can be collected using a single beam polarizingreflectometer system. The spectral data generated by IM module can becompared to the simulated spectra in an ODP/PAS Library. The matchedspectra correspond to a profile with CD, film thickness, and sidewallangle information. Multiple kinds of grating like Iso/Nested can bemeasured in series.

During an iso/nested measurement sequence, the processing tool selectsone IM recipe to use, and separate IMM recipes can be used for iso andnested structures. Each wafer can be measured separately for each pitchand structure.

For example, a wafer can be loaded into an integrated metrology (IM)module; an IM recipe can be loaded into the IM module; and a ProfilerApplication Server (PAS) recipe can be loaded into the IM controller.Next, the wafer can be measured and an ODP recipe can be loaded into theIM controller. The library can then be searched using the measuredspectrum, and one or more isolated structures can be identified. Whenisolated structures are being measured, IM, PAS, and ODP recipes forisolated structures can be used.

Subsequently, another IM recipe can be loaded into an integratedmetrology (IM) module, and another PAS recipe can be loaded into the IMcontroller. The wafer can be measured or previous measurement data canbe used, and another ODP recipe can be loaded into the IM controller.Next, the library can be searched using the measured spectrum, and oneor more nested structures can be identified. When Nested structures arebeing measured, IM, PAS, and ODP recipes for nested structures can beused. The measurement sequence can be performed for one or moredifferent locations on a wafer, and the wafer can be unloaded.

FIG. 4 shows a simplified flow diagram for an etching process on a waferthat comprises a soft mask layer and a bottom anti-reflective coating(BARC) layer in accordance with an embodiment of the invention.Procedure 400 starts in 405. The wafer can be positioned in a processingchamber by a transfer system. One or more of the wafers can bepre-processed in a measurement tool such as an ODP tool.

In 410, the wafer state is determined. The wafer state can be used todetermine the type of processing that is required. For example, thewafer state can be used to determine that a gate stack etch process isrequired. Input data for the wafer can also be received and processed.The input data can comprise configuration information that characterizesthe present state of the wafer and can include at least one of layerdata, soft mask data, BARC data, hard mask data, process result data,model data, historical data, and metrology data for the wafer.

A Soft Mask Iso/nested Control Strategy is determined for the waferusing the wafer state and/or the input data. When a Soft Mask Iso/nestedcontrol strategy is executed, a wafer can be processed in a physicalmodule. Alternately, when the controller determines that a Soft MaskIso/nested control strategy that matches the processing context for awafer does not exist, the controller can create and can execute a newSoft Mask Iso/nested control strategy.

The control strategy selection and initiation can be context-based.Context matching can be implemented using SQL (Structured QueryLanguage) statements that match all recipes that contain the contextitems. Alternately, SQL is not required.

In 415, the isolated data can be determined. Isolated data can be CDdata that was previously measured and/or calculated for one or moreisolated structures on the wafer. When isolated data is required, awafer can be sent to an integrated metrology module (IMM) to bemeasured. An Iso-CD value for the wafer can be computed using data fromone or more locations on the wafer. For example, the Iso-CD value can bean average value, a 1-Sigma value, or a 3-Sigma value. The metrologydata can include reference and/or measured metrology data for at leastone isolated structure on the wafer.

In 420, the nested data can be determined. Nested data can be CD datathat was previously measured and/or calculated for one or more nestedstructures on the wafer. When nested data is required, a wafer can besent to an integrated metrology module (IMM) to be measured. A Nested-CDvalue for the wafer can be computed using data from one or morelocations on the wafer. For example, the Nested-CD value can be anaverage value, a 1-Sigma value, or a 3-Sigma value. The metrology datacan include reference and/or measured metrology data for at least onenested structure on the wafer.

In 425, a query is performed to determine if the Nested-CD value is lessthan the Iso-CD value. When the Nested-CD value is less than the Iso-CDvalue, procedure 400 branches to 430 and continues as shown in FIG. 4.When the Nested-CD value is not less than the Iso-CD value, procedure400 branches to 440 and continues as shown in FIG. 4.

In 430, the control plans associated with an Iso-Greater ControlStrategy in which the Iso-CD value is greater than or equal to theNested-CD value can be executed. The control plans can include at leastone of an Iso/nested control plan for controlling an iso/nested process,a Trim Control plan for controlling a trimming process, and a BARC opencontrol plan for controlling a BARC etching process. When the Iso-CDvalue is equal to the Nested-CD value, or when the required trim amountis substantially equal to zero, or when BARC etching is not required, anull recipe can be sent to the processing tool. Alternately, a recipemay not be sent to the processing tool.

The iso/nested process can include an etching process when the Iso-CDvalue is greater than the Nested-CD value. For example, an iso/nestedetching process can be run using a chamber pressure approximately equalto 10 mT, an upper RF power approximately equal to 200 W, an lower RFpower approximately equal to 0 W; an O₂ flow rate approximately equal to70 sccm, the back side He pressure can be approximately equal to 3 Torrin the center region, the back side He pressure can be approximatelyequal to 3 Torr in the edge region, the top plate temperature can beapproximately equal to 80° C., the chamber wall temperature can beapproximately equal to 60° C., the substrate holder temperature can beapproximately equal to 30° C., and the processing time can beapproximately equal to 36 sec. In addition, the CD change for a nestedfeature was measured to be approximately equal to −23 nm, and the CDchange for isolated feature was measured to be approximately equal to−33 nm.

In one embodiment shown in FIG. 5A, the isolated soft mask (photoresist)feature size can be larger than the nested soft mask (photoresist)feature size, and a first Iso-Greater Control Strategy requires that thetrim process be executed first, the iso/nested etching process beexecuted second, and the BARC open etching process be executed last.

A trim process can be performed first in which substantially the sameamount is trimmed (laterally etched) from the isolated soft maskfeatures and the nested soft mask features. After the trim process isperformed, the isolated soft mask feature size remains larger than thenested soft mask feature size. During a trim process, a hard mask (BARC)layer can be partially etched.

Next, an iso/nested etching process can be performed in which unequalamounts are trimmed (laterally etched) from the isolated soft maskfeatures and the nested soft mask features. After the iso/nested etchingprocess is performed, the isolated soft mask features are substantiallythe same size as the nested soft mask features. During an iso/nestedetching process, a hard mask (BARC) layer can be partially etched.

Finally, a BARC open etching process can be performed in which theremaining BARC is removed between the isolated soft mask features andthe nested soft mask features. After the BARC open etching process isperformed, the isolated soft mask features are substantially the samesize as the nested soft mask features. In addition, the isolated hardmask features are substantially the same size as the nested hard maskfeatures after the BARC open etching process is performed. After theBARC open etching process is performed, the size of the isolated hardmask features and the nested hard mask features is substantially equalto the required CD.

In a second embodiment shown in FIG. 5B, the isolated soft mask(photoresist) feature size can be larger than the nested soft mask(photoresist) feature size, and the second Iso-Greater Control Strategyrequires that the trim process be executed first, the BARC open etchingprocess be executed second, and the iso/nested etching process beexecuted last.

A trim process can be performed first in which substantially the sameamount is trimmed (laterally etched) from the isolated soft maskfeatures and the nested soft mask features. After the trim process isperformed, the isolated soft mask feature size remains larger than thenested soft mask feature size. During a trim process, a hard mask (BARC)layer can be partially etched.

Next, a BARC open etching process can be performed in which theremaining BARC is removed forming isolated hard mask features and nestedhard mask features. After the BARC open etching process is performed,the isolated soft mask features remain larger in size than the nestedsoft mask features. In addition, the hard mask features aresubstantially the same size as the soft mask features after the BARCopen etching process is performed.

Finally, an iso/nested etching process can be performed in which unequalamounts are trimmed (laterally etched) from the isolated soft maskfeatures and the nested soft mask features. In addition, during aniso/nested etching process, unequal amounts are trimmed from theisolated hard mask features and the nested hard mask features. After theiso/nested etching process is performed, the isolated soft mask featuresare substantially the same size as the nested soft mask features. Duringan iso/nested etching process, a hard mask (BARC) layer can be partiallyetched. After the iso/nested etching process is performed, the size ofthe isolated hard mask features and the nested hard mask features issubstantially equal to the required CD.

In a third embodiment shown in FIG. 5C, the isolated soft mask(photoresist) feature size can be larger than the nested soft mask(photoresist) feature size, and a third Iso-Greater Control Strategy canrequire that the iso/nested etching process be executed process beexecuted first, the trim process be executed second, and the BARC openetching process be executed last.

An iso/nested etching process can be performed first in which unequalamounts are trimmed (laterally etched) from the isolated soft maskfeatures and the nested soft mask features. After the iso/nested etchingprocess is performed, the isolated soft mask features are substantiallythe same size as the nested soft mask features. During an iso/nestedetching process, a hard mask (BARC) layer can be partially etched.

Next, a trim process can be performed in which substantially the sameamount is trimmed (laterally etched) from the isolated soft maskfeatures and the nested soft mask features. After the trim process isperformed, the size of the isolated soft mask features remainssubstantially the same as the size of the nested soft mask features.During a trim process, a hard mask (BARC) layer can be partially etched.

Finally, a BARC open etching process can be performed in which theremaining BARC is removed between the isolated soft mask features andthe nested soft mask features. After the BARC open etching process isperformed, the isolated soft mask features are substantially the samesize as the nested soft mask features. In addition, the isolated hardmask features are substantially the same size as the nested hard maskfeatures after the BARC open etching process is performed. After theBARC open etching process is performed, the size of the isolated hardmask features and the nested hard mask features is substantially equalto the required CD.

In a fourth embodiment shown in FIG. 5D, the isolated soft mask(photoresist) feature size can be larger than the nested soft mask(photoresist) feature size, and a fourth Iso-Greater Control Strategycan require that the iso/nested etching process be executed process beexecuted first, the BARC open etching process be executed second, andthe trim process be executed last.

An iso/nested etching process can be performed first in which unequalamounts are trimmed (laterally etched) from the isolated soft maskfeatures and the nested soft mask features. After the iso/nested etchingprocess is performed, the isolated soft mask features are substantiallythe same size as the nested soft mask features. During an iso/nestedetching process, a hard mask (BARC) layer can be partially etched.

Next, a BARC open etching process can be performed in which theremaining BARC is removed between the isolated soft mask features andthe nested soft mask features. After the BARC open etching process isperformed, the isolated soft mask features are substantially the samesize as the nested soft mask features. In addition, the isolated hardmask features are substantially the same size as the nested hard maskfeatures after the BARC open etching process is performed.

Finally, a trim process can be performed in which substantially the sameamount is trimmed (laterally etched) from the isolated soft maskfeatures and the nested soft mask features. In addition, during the trimprocess, substantially the same amount is trimmed from the isolated hardmask features and the nested hard mask features. After the trim processis performed, the size of the isolated hard mask features and the nestedhard mask features is substantially equal to the required CD. After thetrim process, the size of the soft mask features can be equal to or lessthan the size of the hard mask features.

Again referring to FIG. 4, in 430, data collection (DC) plans associatedwith the Iso-Greater Control Strategy can be executed. Data collectionplan applications can run before, during, and/or after control plans areexecuted. Data collection plans can obtain data from processing elementssuch as a tool, a module, a chamber, and a sensor; measuring elementssuch as a OES system, ODP system, a SEM system, a TEM system, and a MESsystem. In addition, the data collection plan selection and initiationcan also be context-based. The DC plan determines which data iscollected, how the data is collected, and where the data is stored. Thecontroller 120 can auto-generate data collection plans for physicalmodules. Typically, one data collection plan can be active at a time fora specific module, and the controller 120 can select and use a datacollection plan that matches the wafer context. Data can include tracedata, process log information, recipe data, maintenance counter data,ODP data, OES data, VIP data, or analog data, or a combination of two ormore thereof. Measurement devices and/or sensors can be started andstopped by a DC plan. A DC plan can also provide information fortrimming data, clipping data, and dealing with spike data and outliers.

In 435, an Iso-Greater Analysis Strategy is determined for the waferusing the wafer data. When an analysis strategy is executed, wafer data,process data, and/or module data can be analyzed, and alarm/faultconditions can be identified.

In addition, the analysis plans associated with the Iso-Greater AnalysisStrategy can be executed. The analysis plans can include at least one ofa Trim Control analysis plan for analyzing a trimming process, aniso/nested analysis plan for analyzing an iso/nested etching process,and a BARC open analysis plan for analyzing a BARC etching process. Inaddition, judgment and/or intervention plans can be executed.

For example, after the data has been collected, the data can be sent toa judgment and/or intervention plan for run-rule evaluation. Faultlimits can be calculated automatically based on historical data orentered manually based on the customer's experience or processknowledge, or obtained from a host computer. The data can be comparedwith the warning and control limits, and when a run-rule is violated, analarm can be generated, indicating the process has exceeded statisticallimits. When an alarm is generated, the controller 120 can performeither notification or intervention. Notification can be via e-mail orby an e-mail activated pager. In addition, the controller 120 canperform an intervention: either pausing the process at the end of thecurrent lot, or pausing the process at the end of the current wafer. Thecontroller 120 can identify the processing module that caused the alarmto be generated.

Results from analysis plans, judgment plans, and intervention plans canfeed forward and/or feedback data to other plans, and the other planscan use this data to calculate their outputs.

After procedure 435 is performed, procedure 400 can continue to 450where it ends.

In 440, the control plans associated with a Nes-Greater Control Strategyin which the Iso-CD value is less than the Nested-CD value can beexecuted. The control plans can include at least one of an Iso/nestedcontrol plan for controlling an iso/nested etching process, a TrimControl plan for controlling a trimming process, and a BARC open controlplan for controlling a BARC etching process.

The iso/nested process can include a deposition process when theNested-CD value is greater than the Iso-CD value. For example, aniso/nested deposition process can be run using a chamber pressureapproximately equal to 10 mT, an upper RF power approximately equal to200 W, an lower RF power approximately equal to 100 W; a CHF₃ flow rateapproximately equal to 200 sccm, the back side He pressure can beapproximately equal to 3 Torr in the center region, the back side Hepressure can be approximately equal to 3 Torr in the edge region, thetop plate temperature can be approximately equal to 80° C., the chamberwall temperature can be approximately equal to 60° C., the substrateholder temperature can be approximately equal to 30° C., and theprocessing time can be approximately equal to 185 sec. In addition, theCD change for a nested feature was measured to be approximately equal to+15 nm, and the CD change for isolated feature was measured to beapproximately equal to +30 nm.

In a fifth embodiment shown in FIG. 6A, the nested soft mask(photoresist) feature size can be greater than the isolated soft mask(photoresist) feature size, and a first Nes-Greater Control Strategyrequires that the trim process be executed first, an iso/nesteddeposition process be executed second, and the BARC open etching processbe executed last.

A trim process can be performed first in which substantially the sameamount is trimmed (laterally etched) from the isolated soft maskfeatures and the nested soft mask features. After the trim process isperformed, the isolated soft mask feature size remains larger than thenested soft mask feature size. During a trim process, a hard mask (BARC)layer can be partially etched.

Next, an iso/nested deposition process can be performed in which unequalamounts are deposited to the isolated soft mask features and the nestedsoft mask features. During the iso/nested deposition process, thedeposition rate can be larger on the isolated features and after thedeposition process is performed the isolated soft mask (photoresist)feature size can be greater than or substantially equal to the nestedsoft mask (photoresist) feature size. During an iso/nested depositionprocess, a hard mask (BARC) layer can be partially coated.

Finally, a BARC open etching process can be performed in which theremaining BARC is removed between the isolated soft mask features andthe nested soft mask features. After the BARC open etching process isperformed, the isolated soft mask features are substantially the samesize as the nested soft mask features. In addition, the isolated hardmask features are substantially the same size as the nested hard maskfeatures after the BAR C open etching process is performed. After theBARC open etching process is performed, the size of the isolated hardmask features and the nested hard mask features is substantially equalto the required CD.

In a sixth embodiment shown in FIG. 6B, the nested soft mask(photoresist) feature size can be greater than the isolated soft mask(photoresist) feature size, and a second Nes-Greater Control Strategyrequires that the trim process be executed first, the BARC open etchingprocess be executed second, and the iso/nested deposition process beexecuted last.

A trim process can be performed first in which substantially the sameamount is trimmed (laterally etched) from the isolated soft maskfeatures and the nested soft mask features. After the trim process isperformed, the isolated soft mask feature size remains larger than thenested soft mask feature size. During a trim process, a hard mask (BARC)layer can be partially etched.

Next, a BARC open etching process can be performed in which theremaining BARC is removed forming isolated hard mask features and nestedhard mask features. After the BARC open etching process is performed,the isolated soft mask features remain larger in size than the nestedsoft mask features. In addition, the hard mask features aresubstantially the same size as the soft mask features after the BARCopen etching process is performed.

Finally, an iso/nested deposition process can be performed in whichunequal amounts are deposited to the isolated soft mask features and thenested soft mask features. During the iso/nested deposition process, thedeposition rate can be larger on the isolated features and after thedeposition process is performed, the isolated soft mask (photoresist)feature size can be greater than or substantially equal to the nestedsoft mask (photoresist) feature size. During an iso/nested depositionprocess, a hard mask (BARC) layer can be partially coated.

In a seventh embodiment shown in FIG. 6C, the nested soft mask(photoresist) feature size can be greater than the isolated soft mask(photoresist) feature size, and a third Nes-Greater Control Strategy canrequire that the iso/nested deposition process be executed process beexecuted first, the trim process be executed second, and the BARC openetching process be executed last.

First, an iso/nested deposition process can be performed in whichunequal amounts are deposited to the isolated soft mask features and thenested soft mask features. During the iso/nested deposition process, thedeposition rate can be larger on the isolated features and after thedeposition process is performed, the isolated soft mask (photoresist)feature size can be greater than or substantially equal to the nestedsoft mask (photoresist) feature size. During an iso/nested depositionprocess, a hard mask (BARC) layer can be partially coated.

Next, a trim process can be performed in which substantially the sameamount is trimmed (laterally etched) from the isolated soft maskfeatures and the nested soft mask features. After the trim process isperformed, the size of the isolated soft mask features remainssubstantially the same as the size of the nested soft mask features.During a trim process, a hard mask (BARC) layer can be partially etched.

Finally, a BARC open etching process can be performed in which theremaining BARC is removed between the isolated soft mask features andthe nested soft mask features. After the BARC open etching process isperformed, the isolated soft mask features are substantially the samesize as the nested soft mask features. In addition, the isolated hardmask features are substantially the same size as the nested hard maskfeatures after the BARC open etching process is performed. After theBARC open etching process is performed, the size of the isolated hardmask features and the nested hard mask features is substantially equalto the required CD.

In an eighth embodiment shown in FIG. 6D, the nested soft mask(photoresist) feature size can be larger than the isolated soft mask(photoresist) feature size, and a fourth Nes-Greater Control Strategycan require that the iso/nested deposition process be executed processbe executed first, the BARC open etching process be executed second, andthe trim process be executed last.

First, an iso/nested deposition process can be performed in whichunequal amounts are deposited to the isolated soft mask features and thenested soft mask features. During the iso/nested deposition process, thedeposition rate can be larger on the isolated features and after thedeposition process is performed, the isolated soft mask (photoresist)feature size can be greater than or substantially equal to the nestedsoft mask (photoresist) feature size. During an iso/nested depositionprocess, a hard mask (BARC) layer can be partially coated.

Next, a BARC open etching process can be performed in which theremaining BARC is removed between the isolated soft mask features andthe nested soft mask features. After the BARC open etching process isperformed, the isolated soft mask features are substantially the samesize as the nested soft mask features. In addition, the isolated hardmask features are substantially the same size as the nested hard maskfeatures after the BARC open etching process is performed.

Finally, a trim process can be performed in which substantially the sameamount is trimmed (laterally etched) from the isolated soft maskfeatures and the nested soft mask features. In addition, during the trimprocess, substantially the same amount is trimmed from the isolated hardmask features and the nested hard mask features. After the trim processis performed, the size of the isolated hard mask features and the nestedhard mask features is substantially equal to the required CD. After thetrim process, the size of the soft mask features can be equal to or lessthan the size of the hard mask features.

Again referring to FIG. 4, in 440, data collection (DC) plans associatedwith the Nes-Greater Control Strategy can be executed. Data collectionplan applications can run before, during, and/or after control plans areexecuted. In addition, the data collection plan selection and initiationcan also be context-based. The DC plan determines which data iscollected, how the data is collected, and where the data is stored. Thecontroller 120 can auto-generate data collection plans for physicalmodules. Typically, one data collection plan can be active at a time fora specific module, and the controller 120 can select and use a datacollection plan that matches the wafer context. Data can include tracedata, process log information, recipe data, maintenance counter data,ODP data, OES data, VIP data, or analog data, or a combination of two ormore thereof. Measurement devices and/or sensors can be started andstopped by a DC plan. A DC plan can also provide information fortrimming data, clipping data, and dealing with spike data and outliers.

In 445, a Nes-Greater Analysis Strategy is determined for the waferusing the wafer data. When an analysis strategy is executed, wafer data,process data, and/or module data can be analyzed, and alarm/faultconditions can be identified.

In addition, the analysis plans associated with the Nes-Greater AnalysisStrategy can be executed. The analysis plans can include at least one ofa Trim Control analysis plan for analyzing a trimming process, aniso/nested analysis plan for analyzing an iso/nested etching process,and a BARC open analysis plan for analyzing a BARC etching process. Inaddition, judgment and/or intervention plans can be executed.

For example, after the data has been collected, the data can be sent toa judgment and/or intervention plan for run-rule evaluation. Faultlimits can be calculated automatically based on historical data orentered manually based on the customer's experience or processknowledge, or obtained from a host computer. The data can be comparedwith the warning and control limits, and when a run-rule is violated, analarm can be generated, indicating the process has exceeded statisticallimits. When an alarm is generated, the controller 120 can performeither notification or intervention. Notification can be via e-mail orby an e-mail activated pager. In addition, the controller 120 canperform an intervention: either pausing the process at the end of thecurrent lot, or pausing the process at the end of the current wafer. Thecontroller 120 can identify the processing module that caused the alarmto be generated.

Results from analysis plans, judgment plans, and intervention plans canfeed forward and/or feedback data to other plans, and the other planscan use this data to calculate their outputs.

After procedure 445 is performed, procedure 400 can continue to 450where it ends. The wafer can be removed from the processing chamber by atransfer system. One or more of the processed wafers can be sent to ameasurement tool such as an ODP tool.

In the illustrated embodiment, a single control strategy is shown, butthis is not required for the invention. One or more control strategiescan be created for each measurement step and/or processing step in aprocess sequence.

A control plan can be coupled to one or more other control plans and oneor more input data items. Results from control plans and data collectionplans can feed forward and/or feedback data to other plans, and theother plans can use this data to calculate their outputs.

Control plans can receive measurement data. The measurement data caninclude “Isolated” data that can include metrology data for at least onearea on the wafer that comprises isolated structures, features,trenches, or vias, or combinations thereof, and can include “Nested”data that can include metrology data for at least one area on the waferthat comprises dense and/or nested structures, features, trenches, orvias, or combinations thereof. Alternately, other data can be includedsuch as a “Reference”, “Mixed”, or “Nominal” data.

The input data can comprise Optical Digital Profilometry (ODP) data froman integrated metrology module (IMM), such as an iODP module from TokyoElectron Ltd. Alternately, the input data may include SEM data and/orTEM data.

Control plans can include data conversion operations. For example, dataconversion can be used to calibrate the “Isolated” data to “CD-SEM”data. An equation and/or table can be established that relates themetrology data for “isolated” structures from one metrology module (IMM)to another metrology module (SEM). In addition, data conversion can beused to calibrate the “Nested” data to “CD-SEM” data. An equation and/ortable can be established that relates the metrology data for “nested”structures from one metrology module (IMM) to another metrology module(SEM). One metrology module may be used to provide “Reference” data.

Control plans can be used to compute one or more recipe parameters, andthe control plan outputs can include one or more recipe parameters forone or more process steps. For example, step time may be a computedrecipe parameter.

A physical module can have at least one control plan defined for eachvisit to the physical module. Control plans contain models, limits,targets, recipes, and can cover multiple process steps within a module.In one embodiment, a Soft Mask Iso/nested Control Strategy and/or plancan be established and mapped to a physical module. Control strategiesand/or plans can be established when a Process Job (PJ) is receivedand/or created.

In one embodiment, the procedure shown in FIG. 4 can be performed in asingle processing chamber such as a TELIUS SCCM Poly Chamber from TokyoElectron Limited (TEL). In alternate embodiments, one or more chamberscan be used. A single chamber procedure provides a lower cost approachfor gate stack etching processes.

FIG. 7 shows an exemplary recipe table in accordance with an embodimentof the invention. In the illustrated embodiment, the trim amount can bechanged by changing, for example, the value of the step time in step 2.In an alternate embodiment, a different parameter can be used to controlthe trim amount.

In addition, the gas chemistry can be changed to control the iso/nestedoffset value.

FIG. 8 shows a graph of exemplary trim equations in accordance with anembodiment of the invention. In the illustrated embodiment, linearequations are shown for an Iso trim amount and a Nest trim amount.Alternately, non-linear equations can be used. In FIG. 8, the graphshows a Trim amount vs. Etching time after a BARC open process has beenperformed.

In one case, the isolated structures etch faster than the Nestedstructures. Alternately, other rates can be used. In addition, theIsolated CDs can be larger than the Nested CDs. Alternately, otherrelationships can be made. In addition, the variation within the nestedCDs can be greater.

In one part of the procedure, an iso-nested bias can be calculated. Forexample, the ODP data for each structure can be correlated to referencedata, such as CD-SEM data.

In one example in which the nested feature size is less than theisolated feature size, the iso-nested delta can be calculated and theODP data can be calibrated to CD-SEM data.

In one embodiment, an measurement grating having a first pitch isprovided that is consistent with the isolated structures/features for aparticular product and technology and another measurement grating havinga second pitch is provided that is consistent with the nestedstructures/features for this product and technology. For example, a 595nm grating can be used for isolated structures and a 245 nm grating canbe used for nested structures. In alternate embodiments, additionalmeasurement gratings may be provided and different pitches may beprovided.

The calculated isolated data value can be determined using:Iso_(c)=Iso_Mandel_Slope*Iso_ODP+Iso_Mandel_InterceptIso_(c)=(1.08*d1+12.27)where Iso_Mandel_Slope is the slope of the line relating the CDSEM datato the ODP data for isolated structures, Iso_ODP is the value of one ofthe ODP measurements for one of the isolated structures;Iso_Mandel_Intercept is the intercept point of the line relating theCDSEM data to the ODP data for isolated structures.

The calculated nested data value can be determined using:Nested_(c)=Nested_Mandel_Slope*Nested_ODP+Nested_Mandel_InterceptNested_(c)=(1.08*d2+12.27)where the Nested_Mandel_Slope is the slope of the line relating theCDSEM data to the ODP data for nested structures, the Nested_ODP is thevalue of one of the ODP measurements for one of the nested structures;and the Nested_Mandel_Intercept is the intercept point of the linerelating the CDSEM data to the ODP data for nested structures.

The difference can beDelta(nm)=Iso_(c)−Nested_(c)

In one case, an iso/nested step time adjustment can be calculated.Delta_Trim(t1)=Delta−Delta_Target (o1)Y=t1=(1.08*d1+12.27)−(1.08*d2+12.27)−o1Recipe Setting=Delta_Trim=y=f(x)Control parameter=Step Process Time (seconds)Delta_Trim (nm)=y=(3.8/15)*xThis equation can be solved for x, and this time can be entered inrecipe step 4 (StepProcessTime)

Next, the remaining Trim based on the amount of Trim made during theIso/Nested trim can be calculated.Delta_Trim=t1=f(d3)Pass t1 from the first control plan (CP1), and assign t1 to d3. Then,calculate the amount of trim in iso/nested calculations where:Delta_Trim=(d3*(18.1/15))

Next, the remaining trim needed can be computed.Trim=Isoc−Target−Delta_Trim Completet1=(1.08*d1+12.27)−o1−(d3*(18.1/15))Trim=y=f(x)Compute “StepProcessTime” as x. For example:y=0.6(x)Solve for x, enter this time in recipe step 2 (StepProcessTime).

Another way to control a soft mask etch process would be to provide anintermediate pitch between either fully nested or isolated. In thiscase, the Iso/nest adjustment could be calculated as previously shown.The trim amount needed could be calculated; the CD of a controlstructure could be determined based on additional measurements; acorrelation could be developed between the control pitch and anotherpitch; the existing measurements could be calibrated to the controlpitch; and the trim amount could be calculated using:Trim amount=CD for control structure−CD target for control structure

Table 1 shows an exemplary set of process parameters for processing awafer having isolated and nested structures. A three-step process(Iso/Nested Trim, BARC, and TRIM) is shown, but this is not required forthe invention. Alternately, a different number of steps may be used andthe steps may be performed in a different order. TABLE 1 Press Power GapCF4 CHF3 CH2F2 O2 N2 Ar H.V. BP(C/E) Temp C. Etching Time Cond (mt) T/B(W) (mm) sccm sccm Sccm sccm sccm sccm (kV) (Torr) T/W/B (Sec)Iso/nested Trim step - Recipe A or Recipe B settings - Based on (Iso >Nested or Iso < Nested) BARC 8 200/75 170 55 7.5 12 2.5 3/3 80/60/75 49TRIM 7 200/75 170 3 50 2.5 3/3 80/60/75 15

The Trim variable value can be approximated using the average value forthe Iso/Nested etch rate, and the step_time variable value can be passedfrom another Control plan. Next, the additional trim (remaining BARCTrim) can be determined based on the amount of BARC Trim made during thebias trim process.

For example:Iso/Nested Trim Amount=(Average Iso Trim Amount/Trim time)*Step_timeIso/Nested Trim Amount=(18.1/15)*Step_timeTrim=Iso_(c)−Iso/Nested Trim Amount−Final CD Target(Iso)

In an alternate embodiment, the calculations can be based on nestedvalues.

In addition, recipe settings for the final BARC trim can be computed.For example, when using a O₂/CF₄ ratio, an equation can be created:BARC_Trim=y=f(x)where x is O₂ flow, andy=48.416083725*(1−0.00388123723/((0.020654293/80)*x+0.0046147421))

In some cases, out of range exceptions may occur. For example, thecalculated Iso/nested value can be larger than total trim value, or theIso value can be larger than the nested incoming CD. One solution wouldbe to check the sign and make a set of computations based on the need togrow nested. When the value is off the iso/nested bias trim curve, themaximum bias adjustment may be used. When the value is off the low endof the trim curve, the solution can be to skip the trim, and when thevalue is off the high end of the trim curve, the solution can be to usemax trim and generate warning to host.

FIG. 9 shows a simplified block diagram of a cascaded control system inaccordance with an embodiment of the invention. In the illustratedembodiment, two strategies A and B are shown. As would be appreciated bythose skilled in the art, however, a control system including only thesetwo strategies, or only two strategies, is not required for theinvention. Alternately, a cascaded control system can comprise multiplestrategies.

Multiple measurement structures can be used for the pre-etch measurementand/or the post-etch measurement process.

FIG. 10 shows a simplified sequence diagram for a method of operating aprocessing system in accordance with an embodiment of the invention. Inthe illustrated embodiment, a cascading feed-forward wafer-to-wafercalculation sequence 1000 is shown, but this is not required for theinvention. Alternately, the sequence can be lot-based or batch-based.

In the illustrated embodiment, sequence 1000 includes two control plansCP1 and CP2, but this is not required for the invention. Alternately, adifferent number of control plans may be used. For example, the controlplans can include at least one of a Trim Control plan for controlling atrimming process, an Iso/Nested control plan for controlling anIso/Nested etching and or deposition process, and a BARC open controlplan for controlling a BARC etching process.

Control plan CP1 can be coupled to a first input element 1010 and caninclude one or more data elements, such as 1020 and 1025. Alternately, adifferent number of input elements and/or data elements can be used. Thedata element 1020 can include “Isolated” data and can include metrologydata for at least one area on the wafer that comprises isolatedstructures, features, trenches, or vias, or combinations thereof. Thedata element 1025 can include “Nested” data and can include metrologydata for at least one area on the wafer that comprises dense and/ornested structures, features, trenches, or vias, or combinations thereof.Alternately, other data elements (not shown) can be included such as a“Reference”, “Mixed”, or “Nominal” data element.

The first input element 1010 can comprise Optical Digital Profilometry(ODP) data from an integrated metrology module (IMM), such as an iODPmodule from Tokyo Electron Ltd. Alternately, the first input element1010 may include SEM data and/or TEM data. The data can comprisemeasured data for at least one of a resist feature, a softmask feature,and a hardmask feature.

The control plan CP1 can also include data conversion elements, such as1030 and 1035. The data conversion element 1030 can be coupled to thedata element 1020 and can be used to convert one or more of the dataitems in the data element 1020. For example, the data conversion element1030 can be used to calibrate the “Isolated” data to “CD-SEM” data. Anequation and/or table can be established that relates the metrology datafor “isolated” structures from one metrology module (IMM) to anothermetrology module (SEM). The data conversion element 1035 can be coupledto the data element 1025 and can be used to convert one or more of thedata items in the data element 1025. For example, the data conversionelement 1035 can be used to calibrate the “Nested” data to “CD-SEM”data. An equation and/or table can be established that relates themetrology data for “nested” structures from one metrology module (IMM)to another metrology module (SEM). One metrology module may be used toprovide “Reference” data.

A second input element 1015 can be coupled to the control plan CP1 andcan comprise input data and/or output data for a process module in aprocessing tool. Alternately, the second input element 1015 may includehistorical data. The second input element 1015 can comprise a desiredvalue for a process result or a process input. For example, the secondinput element 1015 can a “Delta Target” value.

In addition, the control plan CP1 can include one or more computationalelements, such as 1040 and 1045. The computational element 1040 can becoupled to the second input element 1015, the data conversion elements1030, 1035, and to one or more other control plans. In one embodiment,the computational element 1040 can be used to compute one or moreprocessing parameters. For example, the control plan CP1 can be a trimplan for controlling an etch process, and one or more process parameterscan be controlled to optimize the etch process for isolated and/ornested structures. In one case, the desired process result can be a“Delta Trim” value. In another example, the control plan CP1 can be anIso/Nested etching plan for controlling an etch process, and one or moreprocess parameters can be controlled to provide a higher etching ratefor isolated structures. Alternately, a higher etching rate may beprovided for nested structures. In other cases, the desired processresult can be a “Nested Trim” value or an “Isolated Trim” value.

The computational element 1045 can be coupled to the computationalelement 1040, and can provide one or more outputs 1080. In oneembodiment, the computational element 1045 can be used to compute one ormore recipe parameters, and the outputs 1080 can include one or morerecipe parameters for one or more process steps. For example, step timemay be a computed recipe parameter.

A third input element 1060 can be coupled to the second control plan CP2and can comprise input data and/or output data for a process module in aprocessing tool. Alternately, the third input element 1060 may includehistorical data. In one embodiment, the third input element 1060 cancomprise a desired value for a process result or a process input. Forexample, the third input element 1060 can a “Trim Target” value.

The control plan CP2 can be coupled to one or more other control plans,such as the control plan CP1, and can include one or more data elementsfrom other plans, such as the data element 1055. Alternately, adifferent number of control plans and/or data elements can be used. Thedata element 1055 can comprise calculated data from a control plan,collected data from a data collection plan, or data from an analysisplan, or a combination thereof. Alternately, the data element 1055 mayinclude other feed forward and/or feedback data items.

In addition, the second control plan CP2 can include one or morecomputational elements, such as 1065 and 1070. The computational element1065 can be coupled to the data element 1055 and to one or more othercomputational elements in other plans, such as the data conversionelements 1030 and 1035. In one embodiment, the computational element1065 can be used to compute one or more processing parameters. Forexample, the computational element 1065 can be used to compute a “BARCTrim” value using a “Delta Trim” value as an input.

The computational element 1070 can be coupled to the third input element1060, the computational element 1065, and to one or more outputelements, such as the outputs 1080. In one embodiment, the computationalelement 1065 can be used to compute one or more processing parameters.For example, the computational element 1075 can be used to compute a“BARC Trim” value using a “Trim Target” value as an input. Alternately,flow data for one or more process gasses or one or more flow ratios forthe process gasses can be computed. For example, a flow ratio can beprovided for O₂ and CF₄. Alternately, the outputs 1080 may include otherprocess data and/or tool data.

For example, after the data has been collected, the data can be sent toa Fault Detection program for run-rule evaluation. Fault limits can becalculated automatically based on historical data or entered manuallybased on the customer's experience or process knowledge, or obtainedfrom a host computer. The data can be compared with the warning andcontrol limits, and when a run-rule is violated, an alarm can begenerated, indicating the process has exceeded statistical limits. Whenan alarm is generated, the controller 120 can perform eithernotification or intervention. Notification can be via e-mail or by ane-mail activated pager. In addition, the controller 120 can perform anintervention: either pausing the process at the end of the current lot,or pausing the process at the end of the current wafer. The controller120 can identify the processing module that caused the alarm to begenerated.

FIG. 11 shows a simplified sequence diagram for method of operating aprocessing system in accordance with another embodiment of theinvention. In the illustrated embodiment, a feedback flow sequence 1100is shown, but this is not required for the invention. Alternately, thesequence can be a different sequence.

In the illustrated embodiment, the sequence 1100 includes two feedbackplans FB1 and FB2, but this is not required for the invention.Alternately, a different number of feedback plans may be used. Forexample, separate feedback plans may be used for isolated and nestedconditions, and other feedback plans may also be used.

The feedback plan FB1 can be coupled to a first input element 1110 andcan include one or more data elements, such as 1120 and 1125.Alternately, a different number of input elements and/or data elementscan be used. The data element 1120 can include post processed “Iso” dataand can include post process metrology data for at least one area on thewafer that comprises isolated structures/features, trenches, or vias, orcombinations thereof. The data element 1125 can include post processed“Nested” data and can include post process metrology data for at leastone area on the wafer that comprises nested structures/features,trenches, or vias, or combinations thereof. Alternately, other dataelements (not shown) can be included such as a “Reference”, “Mixed”, or“Nominal” data element.

The first input element 1110 can comprise post process ODP data from anintegrated metrology module (IMM), such as an iODP module from TokyoElectron Ltd. Alternately, the first input element 1110 may include postprocess SEM data and/or TEM data. The data can comprise post processmeasured data for at least one of resist features, softmask features,and hardmask features.

The feedback plan FB1 can also include data conversion elements, such as1130 and 1135. The data conversion element 1130 can be coupled to thedata element 1120 and can be used to convert one or more of the postprocessed data items in the data element 1120. For example, the dataconversion element 1130 can be used to calibrate the post-processed“Iso” data to “CD-SEM” data. An equation and/or table can be establishedthat relates the metrology data for “isolated” structures from onemetrology module (IMM) to another metrology module (SEM). The dataconversion element 1135 can be coupled to the data element 1125 and canbe used to convert one or more of the post processed data items in thedata element 1125. For example, the data conversion element 1135 can beused to calibrate the post-processed “Nested” data to “CD-SEM” data. Anequation and/or table can be established that relates the metrology datafor “nested” structures from one metrology module (IMM) to anothermetrology module (SEM). Alternately, “Reference” data may be used. Inaddition, the data conversion element 1130, and the data conversionelement 1135 can be coupled to one or more other plans, such as acontrol plan.

The second input element 1115 can be coupled to the feedback plan FB1and can comprise input data and/or output data for a process module in aprocessing tool, such as a TELIUS™ tool from Tokyo Electron Ltd.Alternately, the second input element 1115 may include historical data.In one embodiment, the second input element 1115 can comprise a desiredvalue for a process parameter, such as a “Delta Target.”

In addition, the feedback plan FB1 can include one or more computationalelements, such as 1140. The computational element 1140 can be coupled tothe second input element 1115, the data conversion elements 1130, 1135,and provide one or more outputs 1150. In one embodiment, thecomputational element 1140 can be used to compute one or more processingparameters. For example, in an etch process, one or more processparameters can be controlled to optimize the etch process for isolatedand/or nested structures. In one case, the process parameter may be a“Delta Error”. Alternately, the outputs 1150 may include other processdata and/or tool data.

The feedback plan FB2 can be coupled to a third input element 1160 andcan include one or more data elements, such as 1165. Alternately, adifferent number of input elements and/or data elements can be used. Thedata element 1165 can include post processed “Iso” data and can includepost process metrology data for at least one area on the wafer thatcomprises isolated structures/features, trenches, or vias, orcombinations thereof. The third input element 1160 can comprise postprocess ODP data from an integrated metrology module (IMM), such as aniODP module from Tokyo Electron Ltd. Alternately, the third inputelement 1160 may include historical data.

In addition, the feedback plan FB2 can include one or more computationalelements, such as 1170 and 1180. The computational element 1170 can becoupled to the data element 1165 and the computational element 1180 andcan provide calibrated data to the computational element 1180. Thecomputational element 1180 can be coupled to a fourth input element 1175and the computational element 1170 and can provide a computed output1185, such as “Trim Error”. In one embodiment, the computational element1180 can be used to compute one or more processing parameters. Forexample, in an etch process, one or more process parameters can becontrolled to optimize the etch process for isolated and/or nestedstructures. In one case, the process parameter may be a “Trim Error”.Alternately, the output 1185 may include other process data and/or tooldata.

FIG. 12 shows a simplified sequence diagram for a method of operating aprocessing system in accordance with another embodiment of theinvention. In the illustrated embodiment, a cascading feed-forward andfeedback wafer-to-wafer calculation sequence 1200 is shown, but this isnot required for the invention. Alternately, the sequence 1200 can belot-based, or batch-based.

In the illustrated embodiment, the sequence 1200 includes two controlplans CP1 and CP2, but this is not required for the invention.Alternately, a different number of control plans may be used. Forexample, separate control plans may be used for isolated and nestedconditions, and other control plans may also be used.

The control plan CP1 can be coupled to a first input element 1210 andcan include one or more data elements, such as 1220 and 1225.Alternately, a different number of input elements and/or data elementscan be used. The data element 1220 can include “Iso” data and caninclude metrology data for at least one area on the wafer that comprisesisolated structures/features, trenches, or vias, or combinationsthereof. The data element 1225 can include “Nested” data and can includemetrology data for at least one area on the wafer that comprises nestedstructures/features, trenches, or vias, or combinations thereof.Alternately, other data elements (not shown) can be included such as a“Reference”, “Mixed”, or “Nominal” data element.

The first input element 1210 can comprise ODP data from an integratedmetrology module (IMM), such as an iODP module from Tokyo Electron Ltd.Alternately, the first input element 1210 may include SEM data and/orTEM data.

The control plan CP1 can also include data conversion elements, such as1230 and 1235. The data conversion element 1230 can be coupled to thedata element 1220 and can be used to convert one or more of the dataitems in the data element 1220. For example, the data conversion element1230 can be used to calibrate the “Iso” data to “CD-SEM” data. Anequation and/or table can be established that relates the metrology datafor “isolated” structures from one metrology module (IMM) to anothermetrology module (SEM). The data conversion element 1235 can be coupledto the data element 1225 and can be used to convert one or more of thedata items in the data element 1225. For example, the data conversionelement 1235 can be used to calibrate the “Nested” data to “CD-SEM”data. An equation and/or table can be established that relates themetrology data for “nested” structures from one metrology module (IMM)to another metrology module (SEM). One metrology module may be used toprovide “Reference” data.

The second input element 1215 can be coupled to the control plan CP1 andcan comprise input data and/or output data for a process module in aprocessing tool, such as a TELIUS™ tool from Tokyo Electron Ltd.Alternately, the second input element 1215 may include historical data.In one embodiment, the second input element 1215 can comprise a desiredvalue for a process parameter, such as a “Delta Target”

The third input element 1212 can be coupled to the control plan CP1 andcan comprise feedback data and/or feed forward data for a process modulein a processing tool, such as a TELIUS™ tool from Tokyo Electron Ltd.Alternately, the third input element 1212 may include historical data.In one embodiment, the third input element 1212 can comprise adifference (error value) between an actual value and a desired value fora process parameter, such as a “Delta Error”

In addition, the control plan CP1 can include one or more computationalelements, such as 1240 and 1245. The computational element 1240 can becoupled to the second input element 1215, the third input element 1212,the data conversion elements 1230, 1235, and to one or more othercontrol plans. In one embodiment, the computational element 1240 can usefeed forward data and feedback data to compute one or more processingparameters. For example, in an etch process, one or more processparameters can be controlled to optimize the etch process for isolatedand/or nested structures. In one case, the feed forward data can include“Delta Target” data, the feedback data can include “Delta Error” data,and the process parameter can include an etch amount, such as a “BiasTrim” value.

The computational element 1245 can be coupled to the computationalelement 1240, and can provide one or more outputs 1280. In oneembodiment, the computational element 1245 can be used to compute one ormore recipe parameters, and the outputs 1280 may include “step time”data for one or more process steps. Alternately, the outputs 1280 mayinclude other process data and/or tool data.

A fourth input element 1260 and a fifth input element 1262 can becoupled to the second control plan CP2 and can comprise input dataand/or output data for a process module in a processing tool, such as aTELIUS™ tool from Tokyo Electron Ltd. Alternately, the fourth and/orfifth input element 1260, 1262 may include historical data. In oneembodiment, the fourth input element 1260 can comprise feed forward datasuch as a desired value for a process result, and the fifth inputelement 1262 can comprise feedback data such as error data for a processresult. For example, the process result can be a “Trim Target”, and theerror data can include a “Trim Error”.

The control plan CP2 can be coupled to one or more other control plans,such as the control plan CP1, and can include one or more data elements,such as 1255. Alternately, a different number of control plans and/ordata elements can be used. The data element 1255 can comprise calculateddata, such as “Bias Trim” data and/or “Step Time” data. Alternately, thedata element 1255 may include other feed forward and/or feedback dataitems.

In addition, the second control plan CP2 can include one or morecomputational elements, such as 1265 and 1270. The computational element1265 can be coupled to the third input element 1260, the data element1255 and to one or more other computational elements, such as 1270. Inone embodiment, the computational element 1265 can be used to computeone or more processing parameters. For example, in an etch process, oneor more process parameters can be controlled to optimize the etchprocess for isolated and/or nested structures. In one case, the processparameter may be a “BARC Trim” and it can be computed using a “DeltaTrim” value.

The computational element 1270 can be coupled to the computationalelement 1265, and can provide one or more outputs 1280. In oneembodiment, the computational element 1270 can be used to compute one ormore recipe parameters, and the outputs 1280 may include flow data forone or more process gasses or one or more flow ratios for the processgasses. For example, a flow ratio can be provided for O₂ and CF₄.Alternately, the outputs 1280 may include other process data and/or tooldata.

FIG. 13 shows exemplary results in accordance with an embodiment of theinvention. In the illustrated embodiment, post lithography results areshown along with post processing results. The data shows excellentuniformity for nested and isolated features for wafers that wereprocessed using the method of the present invention. Two differentsamples that included an ArF Resist were used.

FIG. 14 shows additional exemplary results in accordance with anembodiment of the invention. In the illustrated embodiment, uniformityresults are shown after three different processes. The data showsexcellent uniformity for nested and isolated features across the wafersthat were processed using the method of the present invention.

FIG. 15 shows a simplified flow diagram of another procedure inaccordance with another embodiment of the invention. In the illustratedembodiment, a number of steps (“A”-“F”) are shown, but this is notrequired. Alternately, a different steps and different combinations maybe used.

In step “A”, the wafer is shown in an initial wafer state, and aphotoresist feature is shown on a BARC layer that is coupled to a dopedpoly layer that is coupled to an un-doped poly layer.

In step “B”, the wafer is shown in a second wafer state, and a trimmedphotoresist feature is shown on a partially etched BARC layer that iscoupled to a doped poly layer that is coupled to an un-doped poly layer.A trimming process can be performed to create the second wafer state. Anoptical end point detector (EPD) can be used to determine when thesecond state has been achieved. In one case, the remaining BARC issubstantially equal to the desired final CD. In another case, aniso/nested etch process can be performed to make the remaining BARCsubstantially equal to the desired final CD

In step “C”, the wafer is shown in a third wafer state, and a slightlyreduced photoresist feature is shown on a totally etched BARC layer thatis coupled to a doped poly layer that is coupled to an un-doped polylayer. A BARC open process can be performed to create the third waferstate. An optical end point detector (EPD) can be used to determine whenthe third state has been achieved. In one case, the remaining BARC issubstantially equal to the desired final CD.

In step “D”, the wafer is shown in a fourth wafer state, and a slightlyreduced photoresist feature is shown on a totally etched BARC layer thatis coupled to a totally etched doped poly layer that is coupled to apartially etched un-doped poly layer. A poly etch COE process can beperformed to create the fourth wafer state. An optical end pointdetector (EPD) can be used to determine when the fourth state has beenachieved. In one case, the EPD can be used to determine the amount ofPoly-Si remaining.

In step “E”, a fifth wafer state is shown, and a slightly reducedphotoresist feature is shown on a totally etched BARC layer that iscoupled to a totally etched doped poly layer that is coupled to anearly-completely-etched un-doped poly-Si layer. A first Poly-Si mainetch ME1 process can be performed to create the fifth wafer state, andthe ME1 process uses a faster etch rate to achieve a uniform featureprofile. An optical end point detector (EPD) can be used to determinewhen the fifth state has been achieved. In one case, the EPD can be usedto determine the amount of Poly-Si remaining to ensure a stable profile.

In step “F”, a sixth wafer state is shown, and a slightly reducedphotoresist feature is shown on a totally etched BARC layer that iscoupled to a totally etched doped poly layer that is coupled to atotally-etched un-doped poly-Si layer. A second Poly-Si main etch ME2process and an over-etch OE process can be performed to create the sixthwafer state, and the ME2 process uses a slower etch rate to preserve theuniform feature profile. An optical end point detector (EPD) can be usedto determine when the sixth state has been achieved. In one case, theEPD can be used to determine the amount of Poly-Si remaining to ensure astable profile and the desired CD.

The processing system can include controllers that can operate as asingle input single output (SISO) devices, as a single input multipleoutput (SIMO) devices, as a multiple input single output (MISO) devices,and as a multiple input multiple output (MIMO) devices. In addition,inputs and outputs can be within a controller and/or between one or morecontrollers. For example, when multiple inputs such as CD and sidewallangle are being used, inputs and outputs can be fed forward and backwardbetween two modules, (i.e., one for CD control and one for sidewallangle control). In addition, a mask open controller can also be used. Ina multi-process case including multiple modules, information can befed-forward or fed-back from one controller to another controller.

The previously described feed forward and feedback sequences can beperformed using multiple inputs and/or multiple outputs. The controlplans, recipes, models, data elements, data conversion elements,computational elements, and/or control strategy elements can includemultiple inputs and/or multiple outputs.

In one embodiment, the processing system and the host system cooperateto determine the correct process sequence to use to process a wafer. Forexample, in a trimming process such as a hard mask or a soft mask trimprocess, some wafers may require one pass through an etch module, andother wafers may require more than one pas through an etch module. Inthis case, the host system can allow the processing system to determinethe number of passes through the etch module and control plans and/orstrategies can be established to manage the different number of processobjects in the process sequences for the different wafers.

Furthermore, feedback data can be computed and used to update a processrecipe and/or a process model.

In one embodiment, the processing system controller can determine acontrol strategy (recipe) for each element in a process sequence.Alternately, a control strategy (recipe) may be determined, sent, and/orverified by the host system.

FIG. 16 illustrates an exemplary view of an Iso/Nested Control StrategyScreen in accordance with an embodiment of the invention. An Iso/NestedControl Strategy Screen can comprise a number of configuration items.Using an Iso/Nested Control Strategy Screen, a user can perform anIso/Nested Control Strategy configuration, view an existing Iso/NestedControl Strategy, create a new Iso/Nested Control Strategy, copy anexisting Iso/Nested Control Strategy, edit an existing Iso/NestedControl Strategy, delete an existing Iso/Nested Control Strategy, andtest an Iso/Nested Control Strategy. For example, a dropdown list can beused to select a course of action.

FIG. 17 illustrates an exemplary view of a Nested Control Plan EditorScreen in accordance with an embodiment of the invention.

FIG. 18 illustrates an exemplary view of an Isolated Control Plan EditorScreen in accordance with an embodiment of the invention. Alternately,other plans can be used.

To create a Nested and/or Isolated Control Plan, a user can select theplan name item and select a new Control Plan or an existing plan ormodel. For example, on an Iso/Nested Control Strategy screen, adrop-down menu can appear and the Add Plan selection can be chosen.

A Nested and/or Isolated Control Plan screen can comprise a number offields. The Plan Name field can be used to enter/edit a name for aNested and/or Isolated control plan. A Module field can be used toenter/edit a module name. For example, if the plan is associated with astrategy, the module field may be automatically filled in. If the planis unassociated, the module field can be used to select a process moduleor a measurement module. The Recipe field can be used to enter/edit arecipe. For example, if the plan is associated with a strategy, therecipe field may be automatically filled in. If the plan isunassociated, the field can be used to select a process recipe for aprocess module or a measurement recipe for a measurement module.

The Description field can be used to enter/edit a description for theplan. The Updated field displays the last time the plan was changed.

The Data Sources table can be used to enter/edit a data source. Forexample, a Nested and/or Isolated Plan Data Source screen may be opened.The Data source table can include a source type, a data sourcedescription, and a data source parameter/value. For example, theselected source type determines the options displayed on the Data Sourcescreen; a “Telius ODP” type can be used to define integrated metrologymodule data sources that are part of the processing tool; a “DesiredOutput” type allows the user to enter a fixed unit for the controller; a“Feedback Offset” type allows the user to define a persistent feedbackvariable; a “Control Plan Value” allows the user to create a variablethat references the results of a different control plan (creates nestedplans); the “Integrated Metrology Site Filtering” type creates tableswith descriptions of each option when each data source is selected; anda “ContextItem” type allows a user to create a variable that referencesa context item, such as a Slot_Id, a Wafer_id, or a wafer number.

The symbol can be selected from the Symbol drop-down list, and a sourcetype can be selected from the Data Source Type drop-down menu. Forexample, the data source information fields can vary depending on thechosen data source.

Three input data sources (d1, d2, d3) are shown, but this is notrequired. A different number of input data sources can be used, and eachinput data source can have a different symbol value. A data source canbe a control plan value such as a desired process result or a calibrateddate item. In addition, a data source can be an ODP tool, and it can bepart of the processing tool, such as a Telius. Furthermore, another datasource can be a SEM, and the Parameter/Value can be actual measured datasuch as a CD-SEM data.

In general, process control can include updating a process module recipeusing metrology information measured on the wafer prior to its arrivalin the process module. The controller can use the pre-processing data todetermine how many visits are required to the various physical modules.The desired process result can be a “y” value in a model equation. Thetask is determine when the desired process result “y” is the correctvalue.

In the target calculation field, on a Nested and/or Isolated ControlPlan screen, the target calculation can be entered. For example, thetarget calculation can be set equal to the data source item.Alternately, an equation may be entered that correlates one set of datawith another set of data. In addition, target calculation may comprisean additional compensation term. For example, the additionalcompensation factor can be used to correct for errors introduced inanother step, such as a photo resist step. A new target value can be avariable that is calculated at or before run time, and an equation canbe used to calculate the target value.

In addition, new lower and upper limit values can be used, and thesevalues can be entered in the lower limit field and upper limit field.For example, the new lower and upper limit values can be constants orvariables that are calculated at or before run time, and equations canbe used to calculate the new lower and upper limit values.

The Model Selections field can be used to edit/enter a static modeland/or a formula model. For example, under the model type selectionitem, a selection item in the table can be used to enter and/or edit amodel type. A drop down list can be activated from the table item and aselection can be made from the drop down list. One option in the dropdown list allows a new model to be created; other options can be used todisplay and select existing models to use or to modify. Each model typecan have a module name, target value, lower limit, upper limit, andrecipe output associated with it. When creating a new model, a new modeltype can be used and entered in the model type field, and a new modelname can be used and entered in the model name field.

The Predicted Result Calculation field can be used to enter a newpredicted result value or select an existing predicted result value. Thepredicted result value can be an equation for the expected result. Forexample, a Control Plan can be saved when Name, Target Calculation, andModel Selection information is entered.

The # field comprises a number of the model in the list of models. Themodel type allows either a Static or a Formula model to be selected. TheModel Name field lists the names of available models. For example, tocreate a new model, a “New Static Recipe” option or a “New FormulaRecipe” option can be selected from a drop down list. A static controlplan can be created that comprises one or more static recipes. Forexample, ten or more static models can be shown. The static models areshown with the same target value (t1), but this is not required. Adifferent number of static and/or formula models can be used, and eachmodel can have a different target value. A new target value can becalculated when each static recipe is used. The static recipe models canhave different operating ranges as defined by the lower limit values andthe upper limit values. In addition, the static recipe models can havedifferent static recipe outputs, and a different static recipe outputcan be determined for each static recipe.

The Nested and/or Isolated control plan can include a static modelrecipe, or a formula model recipe, or a combination thereof. Thecontroller can auto-generate control plans for modules. A process recipecan comprise one or more processes each comprising one or moreprocessing steps. The process recipe can be performed in a singlechamber or multiple chambers. The process recipe can be configured usingat least one of a nominal recipe, a static recipe, and a formula model.

A static recipe can be a single set of recipe adjustments that are usedto achieve a specific process result. A set of static recipes can beused to set up a table-based controller, or static recipes can be usedalong with formula models to treat ranges of the desired output wherethe same recipe should be used. When using feedback with static recipes,a single predicted process result can be specified in the control planfor each static recipe used.

FIG. 19 illustrates an exemplary view of a Formula Model Editor Screenin accordance with an embodiment of the invention. A formula model cancomprise a pre-model adjustment, a model equation, a series of postmodel adjustments, and a recipe parameter assignment map. The pre-modeladjustment can allow the re-expression of the desired process result(usually t1) into the correct units that are used in a model equation(resulting in a value of y), and the model equation can be an expressionthat calculates the predicted process result as a function of onemanipulated variable (x). When the model is executed, it will solve forx given the re-expressed desired process result (y). Once x isdetermined, the post model adjustments can be calculated, and theirvalues will be assigned to the appropriate recipe parameters specifiedin the recipe parameter map.

In addition, one or more process models can be provided. A process modelcan be used to define a process space. A process model represents theverified relationship between the desired results (outputs) and thereceived variables needed to achieve those results. Process models caninclude equations that can include formula-based models. Formula-basedmodels can comprise equations that contain the piecewise associations ofdesired results with recipe variables based on some evaluatedexperimental data. A process model can be linear or non-linear. Aprocess model can be used to verify a new process recipe, and update anexisting process recipe.

Although only certain embodiments of this invention have been describedin detail above, those skilled in the art will readily appreciate thatmany modifications are possible in the embodiments without materiallydeparting from the novel teachings and advantages of this invention.Accordingly, all such modifications are intended to be included withinthe scope of this invention.

1. A method of operating a semiconductor processing system comprising:receiving a wafer comprising a soft mask layer and a bottomanti-reflective coating (BARC) layer; receiving reference metrology datafor at least one isolated structure on the wafer, reference metrologydata for at least one nested structure on the wafer, soft mask data, andBARC data; determining a first value comprising measured size data forthe at least one isolated structure on the wafer; determining a secondvalue comprising measured size data for the at least one nestedstructure on the wafer; executing an Iso-Greater control strategy whenthe first value is greater than the second value, wherein theIso-Greater control strategy comprises an Iso/Nested control plan forcontrolling an iso/nested etching process, a Trim Control plan forcontrolling a trimming process, or a BARC open control plan forcontrolling a BARC etching process, or a combination of two or morethereof; and executing a Nes-Greater control strategy when the firstvalue is less than the second value, wherein the Nes-Greater controlstrategy comprises an Iso/Nested control plan for controlling aniso/nested deposition process, a Trim Control plan for controlling atrimming process, or a BARC open control plan for controlling a BARCetching process, or a combination of two or more thereof.
 2. The methodas claimed in claim 1, wherein executing the Iso-Greater controlstrategy further comprises: determining a desired target value for aniso/nested etching process, the desired target value comprising adesired feature size after performing the iso/nested etching process;calculating an iso-trim value using the difference between the firstvalue and the desired target value; calculating a dense-trim value usingthe difference between the second value and the desired target value;calculating a ratio using the iso-trim value and the dense-trim value;executing the iso/nested etching process, wherein recipe settings forachieving the desired target value have been determined using thecalculated ratio; determining a final critical dimension (CD) target;calculating a trim value using a difference between the final CD targetand the desired target value; and executing a trim process, whereinrecipe settings for achieving the final CD target have been determinedusing the trim value.
 3. The method as claimed in claim 2, furthercomprising: executing a bottom anti-reflective coating (BARC) openprocess.
 4. The method as claimed in claim 1, wherein executing theIso-Greater control strategy further comprises: determining a desiredtrim value for a trim process, the desired trim value comprising a trimamount to be removed from the first value and the second value afterperforming the trim process; executing the trim process, wherein recipesettings for achieving the desired trim value have been determined toachieve a first trimmed value and a second trimmed value; determining afinal CD value; calculating an iso-trim value using the differencebetween the first trimmed value and the final CD value, wherein thefirst trimmed value comprises the measured data for an isolatedstructure less the trim amount; calculating a dense-trim value using thedifference between the second trimmed value and the final CD value,wherein the second trimmed value comprises measured data for a nestedstructure less the trim amount; calculating a ratio using the iso-trimvalue and the dense-trim value; and executing the iso/nested etchingprocess, wherein recipe settings for achieving the final CD value havebeen determined using the calculated ratio.
 5. The method as claimed inclaim 4, further comprising: executing a bottom anti-reflective coating(BARC) open process.
 6. The method as claimed in claim 1, wherein theexecuting an Iso-Greater control strategy further comprises: determininga desired target value for an iso/nested etching process, the desiredtarget value comprising a desired feature size after performing theiso/nested etching process; calculating an iso-trim value using thedifference between the first value and the target value; calculating adense-trim value using the difference between the second value and thetarget value; calculating a ratio using the iso-trim value and thedense-trim value; executing the iso/nested etching process, whereinrecipe settings for achieving the desired target value have beendetermined using the calculated ratio; executing a bottomanti-reflective coating (BARC) open process; determining a finalcritical dimension (CD) target; calculating a trim value using adifference between the final CD target and the desired target value; andexecuting a trim process, wherein recipe settings for achieving thefinal CD target have been determined using the trim value.
 7. The methodas claimed in claim 1, wherein executing the Iso-Greater controlstrategy further comprises: determining a desired trim value for a trimprocess, the desired trim value comprising a trim amount to be removedfrom the first value and the second value after performing the trimprocess; executing the trim process, wherein recipe settings forachieving the desired trim value have been determined to achieve a firsttrimmed value and a second trimmed value; executing a bottomanti-reflective coating (BARC) open process; determining a final CDvalue; calculating an iso-trim value using the difference between thefirst trimmed value and the final CD value; calculating a dense-trimvalue using the difference between the second trimmed value and thefinal CD value; calculating a ratio using the iso-trim value and thedense-trim value; and executing the iso/nested etching process, whereinrecipe settings for achieving the final CD value have been determinedusing the calculated ratio.
 8. The method as claimed in claim 1, whereinthe executing a Nes-Greater control strategy further comprises:determining a desired target value for an iso/nested deposition process,the target value comprising a desired feature size after performing theiso/nested deposition process; calculating an iso-trim value using thedifference between the first value and the target value; calculating adense-trim value using the difference between the second value and thetarget value; calculating a ratio using the iso-trim value and thedense-trim value; executing the iso/nested deposition process, whereinrecipe settings for achieving the desired target value have beendetermined using the calculated ratio; determining a final criticaldimension (CD) target; calculating a trim value using a differencebetween the final CD target and the desired target value; and executinga trim process, wherein recipe settings for achieving the final CDtarget have been determined using the trim value.
 9. The method asclaimed in claim 8, further comprising: executing a bottomanti-reflective coating (BARC) open process.
 10. The method as claimedin claim 1, wherein the executing a Nes-Greater control strategy furthercomprises: determining a desired trim value for a trim process, thedesired trim value comprising a trim amount to be removed from the firstvalue and the second value after performing the trim process; executingthe trim process, wherein recipe settings for achieving the desired trimvalue have been determined to achieve a first trimmed value and a secondtrimmed value; determining a final CD value; calculating an iso-trimvalue using the difference between the first trimmed value and the finalCD value, wherein the first trimmed value comprises the measured datafor an isolated structure less the trim amount; calculating a dense-trimvalue using the difference between the second trimmed value and thefinal CD value, wherein the second trimmed value comprises measured datafor a nested structure less the trim amount; calculating a ratio usingthe iso-trim value and the dense-trim value; and executing theiso/nested deposition process, wherein recipe settings for achieving thefinal CD value have been determined using the calculated ratio.
 11. Themethod as claimed in claim 10, further comprising: executing a bottomanti-reflective coating (BARC) open process.
 12. The method as claimedin claim 1, wherein executing the Nes-Greater control strategy furthercomprises: determining a desired target value for an iso/nesteddeposition process, the target value comprising a desired feature sizeafter performing the iso/nested deposition process; calculating aniso-trim value using the difference between the first value and thetarget value; calculating a dense-trim value using the differencebetween the second value and the target value; calculating a ratio usingthe iso-trim value and the dense-trim value; executing the iso/nesteddeposition process, wherein recipe settings for achieving the desiredtarget value have been determined using the calculated ratio; executinga bottom anti-reflective coating (BARC) open process; determining afinal critical dimension (CD) target; calculating a trim value using adifference between the final CD target and the desired target value; andexecuting a trim process, wherein recipe settings for achieving thefinal CD target have been determined using the trim value.
 13. Themethod as claimed in claim 1, wherein executing the Nes-Greater controlstrategy further comprises: determining a desired trim value for a trimprocess, the desired trim value comprising a trim amount to be removedfrom the first value and the second value after performing the trimprocess; executing the trim process, wherein recipe settings forachieving the desired trim value have been determined to achieve a firsttrimmed value and a second trimmed value; executing a bottomanti-reflective coating (BARC) open process; determining a final CDvalue; calculating an iso-trim value using the difference between thefirst trimmed value and the final CD value, wherein the first trimmedvalue comprises the measured data for an isolated structure less thetrim amount; calculating a dense-trim value using the difference betweenthe second trimmed value and the final CD value, wherein the secondtrimmed value comprises measured data for a nested structure less thetrim amount; calculating a ratio using the iso-trim value and thedense-trim value; and executing the iso/nested deposition process,wherein recipe settings for achieving the final CD value have beendetermined using the calculated ratio.
 14. The method as claimed inclaim 1, further comprising: obtaining measurement data for at least oneisolated structure on the wafer, wherein the measurement data isobtained using Optical Digital Profilometry (ODP); establishing a firstequation relating the measurement data to the reference metrology datafor at least one isolated structure on the wafer, wherein the referencemetrology data is obtained using a CDSEM; and determining the firstvalue using the first equation.
 15. The method as claimed in claim 14,wherein the at least one isolated structure comprises a grating pattern.16. The method as claimed in claim 1, further comprising: obtainingmeasurement data for at least one nested structure on the wafer, whereinthe measurement data is obtained using Optical Digital Profilometry(ODP); establishing a first equation relating the measurement data tothe reference metrology data for at least one nested structure on thewafer, wherein the reference metrology data is obtained using a CDSEM;and determining the second value using the first equation.
 17. Themethod as claimed in claim 16, wherein the at least one nested structurecomprises a grating pattern.
 18. The method as claimed in claim 1,further comprising: determining the first value, or the second value, ora combination thereof using historical data.
 19. The method as claimedin claim 1, further comprising: creating a process recipe forcontrolling the iso/nested etching process, wherein the process recipecomprises: establishing a chamber pressure between approximately 5 mTand approximately 25 mT; establishing an upper RF power betweenapproximately 100 W and approximately 300 W; establishing an O₂ flowrate between approximately 50 sccm and approximately 150 sccm;establishing a back side He pressure between approximately 1 Torr andapproximately 5 Torr in a center region and an edge region of asubstrate holder; establishing a top plate temperature betweenapproximately 60° C. and approximately 100° C.; establishing a chamberwall temperature between approximately 40° C. and approximately 80° C.;establishing a substrate holder temperature between approximately 20° C.and approximately 40° C.; and establishing a processing time fromapproximately 30 sec to approximately 120 sec.
 20. The method as claimedin claim 1, further comprising: creating a process recipe forcontrolling the iso/nested deposition process, wherein the processrecipe comprises: establishing a chamber pressure between approximately5 mT and approximately 25 mT; establishing an upper RF power betweenapproximately 100 W and approximately 300 W; establishing a lower RFpower between approximately 0 W and approximately 200 W; establishing aCHF₃ flow rate between approximately 150 sccm and approximately 250sccm; establishing a back side He pressure between approximately 1 Torrand approximately 5 Torr in a center region and an edge region of asubstrate holder; establishing a top plate temperature betweenapproximately 60° C. and approximately 100° C.; establishing a chamberwall temperature between approximately 40° C. and approximately 80° C.;establishing a substrate holder temperature between approximately 20° C.and approximately 40° C.; and establishing a processing time fromapproximately 50 sec to approximately 200 sec.
 21. The method as claimedin claim 1, further comprising: creating a process recipe forcontrolling the trimming process, wherein the process recipe comprises:establishing a chamber pressure between approximately 5 mT andapproximately 10 mT; establishing an upper RF power betweenapproximately 100 W and approximately 300 W; establishing a lower RFpower between approximately 0 W and approximately 150 W; establishing anO₂ flow rate between approximately 5 sccm and approximately 25 sccm;establishing a N₂ flow rate between approximately 5 sccm andapproximately 25 sccm; establishing a back side He pressure betweenapproximately 1 Torr and approximately 5 Torr in a center region and anedge region of a substrate holder; establishing a top plate temperaturebetween approximately 60° C. and approximately 100° C.; establishing achamber wall temperature between approximately 40° C. and approximately80° C.; establishing a substrate holder temperature betweenapproximately 55° C. and approximately 95° C.; and establishing aprocessing time from approximately 5 sec to approximately 50 sec. 22.The method as claimed in claim 1, further comprising: creating a processrecipe for controlling the BARC etching process, wherein the processrecipe comprises: establishing a chamber pressure between approximately5 mT and approximately 15 mT; establishing an upper RF power betweenapproximately 100 W and approximately 300 W; establishing a lower RFpower between approximately 0 W and approximately 150 W; establishing aCF₄ flow rate between approximately 25 sccm and approximately 125 sccm;establishing a CH₂F₂ flow rate between approximately 3 sccm andapproximately 15 sccm; establishing an O₂ flow rate betweenapproximately 5 sccm and approximately 25 sccm; establishing a back sideHe pressure between approximately 1 Torr and approximately 5 Torr in acenter region and an edge region of a substrate holder; establishing atop plate temperature between approximately 60° C. and approximately100° C.; establishing a chamber wall temperature between approximately40° C. and approximately 80° C.; establishing a substrate holdertemperature between approximately 55° C. and approximately 95° C.; andestablishing a processing time from approximately 5 sec to approximately100 sec.
 23. A computer readable medium containing program instructionsfor execution on a computer system coupled to a semiconductor processingsystem, which when executed by the computer system, cause thesemiconductor processing system to perform a process, comprising:receiving a wafer comprising a soft mask layer and a bottomanti-reflective coating (BARC) layer; receiving reference metrology datafor at least one isolated structure on the wafer, reference metrologydata for at least one nested structure on the wafer, soft mask data, andBARC data; determining a first value comprising measured size data forthe at least one isolated structure on the wafer; determining a secondvalue comprising measured size data for the at least one nestedstructure on the wafer; executing an Iso-Greater control strategy whenthe first value is greater than the second value, wherein theIso-Greater control strategy comprises an Iso/Nested control plan forcontrolling an iso/nested etching process, a Trim Control plan forcontrolling a trimming process, or a BARC open control plan forcontrolling a BARC etching process, or a combination of two or morethereof; and executing a Nes-Greater control strategy when the firstvalue is less than the second value, wherein the Nes-Greater controlstrategy comprises an Iso/Nested control plan for controlling aniso/nested deposition process, a Trim Control plan for controlling atrimming process, or a BARC open control plan for controlling a BARCetching process, or a combination of two or more thereof.